Copyright © 2012 W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
Grid Layout contains features targeted at web application authors. The Grid can be used to achieve many different layouts. It excels at dividing up space for major regions of an application, or defining the relationship in terms of size, position, and layer between parts of a control built from HTML primitives.
Like tables, the Grid enables an author to align elements into columns and rows, but unlike tables, the Grid doesn't have content structure, and thus enables a wide variety of layouts not possible with tables. For example, the children of the Grid can position themselves with Grid lines such that they overlap and layer similar to positioned elements.
In addition, the absence of content structure in the Grid helps to manage changes to layout by using fluid and source order independent layout techniques. By combining media queries with the CSS properties that control layout of the Grid and its children, authors can adapt their layout to changes in device form factors, orientation, and available space, without needing to alter the semantic nature of their content.
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Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.
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This document was produced by the CSS Working Group (part of the Style Activity).
This document was produced by a group operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures made in connection with the deliverables of the group; that page also includes instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.
See also the section Changes from Previous Working Draft.
This CSS3 module has normative references to the following other CSS3 modules:
This CSS3 module has non-normative (informative) references to the following other CSS3 modules:
Application layout example requiring horizontal and vertical alignment.
As websites evolved from simple documents into complex, interactive applications, tools for document layout, e.g. floats, were not necessarily well suited for application layout. By using a combination of tables, JavaScript, or careful measurements on floated elements, authors discovered workarounds to achieve desired layouts. Layouts that adapted to the available space were often brittle and resulted in counter-intuitive behavior as space became constrained. As an alternative, authors of many web applications opted for a fixed layout that cannot take advantage of changes in the available rendering space on a screen.
The layout capabilities of the Grid address these problems. The Grid provides a mechanism for authors to divide available space for layout into columns and rows using a set of predictable sizing behaviors. Authors can then precisely position and size the building block elements of their application by referencing the Grid lines between the columns and rows, or by defining and referencing a Grid cell, which is a rectangular space covering an intersection of columns and rows. Figure 1 illustrates a basic layout which can be achieved with the Grid.
Five grid items arranged according to content size and available space.
Growth in the grid due to an increase in available space.
The Grid element can be used to intelligently reflow elements within a webpage. Figure 2 represents a game with five major areas in the layout: the game title, stats area, game board, score area, and control area. The author's intent is to divide the space for the game such that:
As an alternative to using script to control the absolute position, width, and height of all elements, the author can use the Grid element, as shown in Figure 3. The following example shows how an author might achieve all the sizing, placement, and alignment rules declaratively.
Note that there are multiple ways to specify the structure of the Grid element and to position and size Grid items, each optimized for different
scenarios. This example illustrates one that an author may use to define
the position and space for each Grid
item using the ‘grid-rows
’ and ‘grid-columns
’
properties of the Grid element, and
the ‘grid-row
’, ‘grid-column
’,
‘grid-row-span
’ and ‘grid-column-span
’ properties on each Grid item.
<style type="text/css"> #grid { display: grid; /* Two columns: the first sized to content, the second receives the remaining space, */ /* but is never smaller than the minimum size of the board or the game controls, which */ /* occupy this column. */ grid-columns: auto minmax(min-content, 1fr); /* Three rows: the first and last sized to content, the middle row receives the */ /* remaining space, but is never smaller than the minimum height of the board or stats */ /* areas. */ grid-rows: auto minmax(min-content, 1fr) auto } /* Each part of the game is positioned between grid lines by referencing the starting grid */ /* line and then specifying, if more than one, the number of rows or columns spanned to */ /* determine the ending grid line, which establishes bounds for the part. */ #title { grid-column: 1; grid-row: 1 } #score { grid-column: 1; grid-row: 3 } #stats { grid-column: 1; grid-row: 2; grid-row-align: start } #board { grid-column: 2; grid-row: 1; grid-row-span: 2 } #controls { grid-column: 2; grid-row: 3; grid-column-align: center } </style> <div id="grid"> <div id="title">Game Title</div> <div id="score">Score</div> <div id="stats">Stats</div> <div id="board">Board</div> <div id="controls">Controls</div> </div>
An arrangement suitable for ‘portrait
’ orientation.
An arrangment suitable for ‘landscape
’ orientation.
Continuing the prior example, the author also wants the game to adapt to the space available on traditional computer monitors, handheld devices, or tablet computers. Also, the game should optimize the placement of the components when viewed either in landscape or portrait orientation (Figures 4 and 5). By combining the CSS markup for the Grid element with media queries, the author is able to use the same semantic markup, but rearranged independent of its source order, to achieve the desired layout in both orientations.
The following example leverages the Grid element’s ability to name the space which will be occupied by a Grid item. This allows the author to avoid rewriting rules for Grid items as the Grid element’s definition changes.
<style type="text/css"> @media (orientation: portrait) { #grid { display: grid; /* The rows, columns and cells of the grid are defined visually using the */ /* grid-template property. Each string is a row, and each letter a cell. */ /* The max number of letters in any one string determines the number of */ /* columns. */ grid-template: "ta" "sa" "bb" "cc"; /* Columns and rows created with the template property can be assigned a sizing */ /* function with the grid-columns and grid-rows properties. */ grid-columns: auto minmax(min-content, 1fr); grid-rows: auto auto minmax(min-content, 1fr) auto } } @media (orientation: landscape) { #grid { display: grid; /* Again the template property defines cells of the same name, but this time */ /* positioned differently to better suit a landscape orientation. */ grid-template: "tb" "ab" "sc"; grid-columns: auto minmax(min-content, 1fr); grid-rows: auto minmax(min-content, 1fr) auto } } /* The grid-cell property places a grid item into named region (cell) of the grid. */ #title { grid-cell: "t" } #score { grid-cell: "s" } #stats { grid-cell: "a" } #board { grid-cell: "b" } #controls { grid-cell: "c" } </style> <div id="grid"> <div id="title">Game Title</div> <div id="score">Score</div> <div id="stats">Stats</div> <div id="board">Board</div> <div id="controls">Controls</div> </div>
A control composed of layered HTML elements.
In the example shown in Figure 6, the author is creating a custom slider control. The control has six parts. The lower and upper labels align to the left and right edges of the control. The track of the slider spans the area between the labels. The lower and upper fill parts touch beneath the thumb, and the thumb is a fixed width and height that can be moved along the track by updating the two fraction-sized columns.
Prior to the Grid element, the
author would have likely used absolute positioning to control the top
and left coordinates, along with the width and height of each HTML
element that comprises the control. By leveraging the Grid element, the author can instead
limit script usage to handling mouse events on the thumb, which snaps to
various positions along the track as the ‘grid-columns
’
property of the Grid element is
updated.
<style type="text/css"> #grid { display: grid; /* The grid-columns and rows properties also support naming grid lines which can then */ /* be used to position grid items. The line names are assigned on either side of a */ /* column or row sizing function where the line would logically exist. */ grid-columns: "start" auto "track-start" 0.5fr "thumb-start" auto "fill-split" auto "thumb-end" 0.5fr "track-end" auto "end"; } /* Grid-column and grid-row accept a starting and optional endling line. Below the lines */ /* are referred to by name. Beyond any semantic advantage, the names also allow the author */ /* to avoid renumbering the grid-row and column properties of the grid items. This is */ /* similar to the concept demonstrated in the prior example with the grid-template */ /* property during orientation changes, but grid lines can also work with layered grid */ /* items that have overlapping cells of different shapes like the thumb and track parts */ /* in this example. */ #lower-label { grid-column: "start" } #track { grid-column: "track-start" "track-end"; grid-row-align: center } #upper-label { grid-column: "track-end"; } /* Fill parts are drawn above the track so set z-index to 5. */ #lower-fill { grid-column: "track-start" "fill-split"; grid-row-align: center; z-index: 5 } #upper-fill { grid-column: "fill-split" "track-end"; grid-row-align: center; z-index: 5 } /* Thumb is the topmost part; assign it the highest z-index value. */ #thumb { grid-column: "thumb-start" "thumb-end"; z-index: 10 } </style> <div id="grid"> <div id="lower-label">Lower Label</div> <div id="upper-label">Upper Label</div> <div id="track">Track</div> <div id="lower-fill">Lower Fill</div> <div id="upper-fill">Upper Fill</div> <div id="thumb">Thumb</div> </div>
A diagram illustrating the relationship between the Grid element and its Tracks, Lines, Cells and Items.
A Grid element is declared in markup by
setting the display property of an element to ‘grid
’ or ‘inline-grid
’. Child
elements of the Grid are termed Grid
items and may be positioned and sized by the Grid element by leveraging the following
logical concepts.
Figure 7 illustrates the relationship between these concepts and the markup in the subsections that follow produce the result shown in the figure.
Grid Tracks are the columns and rows of the
Grid defined with the ‘grid-rows
’ and ‘grid-columns
’
properties on the Grid element. Each
Track is defined by declaring a sequential list of sizing functions, one
for each Track. Tracks define the space between Grid lines.
<style type="text/css"> #grid { display: grid; grid-columns: 150px 1fr; /* two columns */ grid-rows: 50px 1fr 50px /* three rows */ } </style>
Grid Lines are the horizontal or vertical
dividing lines that exist on either side of a column or row. Grid lines may be referred to by their Grid line number, or they may be named by
the author. Authors use one or more quoted strings to assign names to a
Grid line before or after a Grid track definition wherever the desired
Grid line would logically exist. A Grid item then uses the Grid lines to determine its position and
available space within the Grid by referencing the Grid lines using the properties ‘grid-row
’ and
‘grid-column
’. ‘grid-row
’ and
‘grid-column
’ accept a starting and
optional ending Line.
The following two examples create three column Grid lines and four row Grid lines. The first example demonstrates how an author would refer to the Grid lines using Grid line numbers. The second example uses explicitly named Grid lines.
<style type="text/css"> #grid { display: grid; grid-columns: 150px 1fr; grid-rows: 50px 1fr 50px } #item1 { grid-column: 2; grid-row: 1 4 } </style>
<style type="text/css"> /* equivalent layout to the prior example, but using named lines */ #grid { display: grid; grid-columns: 150px "item1-start" 1fr "item1-end"; grid-rows: "item1-start" 50px 1fr 50px "item1-end" } #item1 { grid-column: "item1-start" "item1-end"; grid-row: "item1-start" "item1-end" } </style>
Grid Cells are the logical space used
to lay out one or more Grid items. Grid cells may be defined
explicitly using the ‘grid-template
’ property, or implicitly
by referencing a region of the Grid using the properties ‘grid-row
’ and
‘grid-column
’ on a Grid item.
Whether a Grid cell is created explicitly or implicitly, there is no difference in the layout or drawing order of the Grid items which are associated with that Grid cell. Grid cells cannot be styled. Only the syntax used to refer to a region of space on the Grid differs between the implicit and explicit approach to provide authors with the tools to best suit their scenarios as illustrated in prior examples.
<style type="text/css"> /* using the template syntax */ #grid { display: grid; grid-template: "ad" "bd" "cd"; grid-columns: 150px 1fr; grid-rows: 50px 1fr 50px } #item2 { grid-cell: "b" } #item3 { grid-cell: "b" } /* Align items 2 and 3 at different points in the Grid Cell "b". */ /* By default, Grid Items are stretched to fit their Grid Cell */ /* and these items would layer one over the other. */ #item2 { grid-row-align: start } #item3 { grid-column-align: end; grid-row-align: end }</style>
A Grid element is declared by setting the display property.
Name: | display |
Value: | [ ...existing values... | grid | inline-grid | |
Computed value: | specified value |
The Grid element performs layout on Grid items. Grid Items are considered block-level children, replaced, inline-block children, and atomic, inline-level children of the Grid element.
Contiguous runs of non-replaced, inline content are wrapped in an anonymous, block-level box, which is then treated as a Grid item for the purposes of Grid layout. Out-of-flow elements (except floats, which are out-of-flow, but are irrelevant to Grid layout since Grid items can't float) leave behind a "placeholder" in their original source location which is treated like a non-replaced, inline element for the purpose of this wrapping. Any indirect descendants of the Grid element, including block elements that are contained in inline elements, are not Grid items.
The following example produces two Grid
Items: the first Grid item is the
anonymous block-level box wrapping the A
and the subsequent
<span>
; the second Grid
item is created by the block-level box of the C
<div>
.
<div style="display:grid;">A<span>B</span><div>C</div></div>
Grid Lines.
Grid elements use Grid lines to divide their space. There are two sets of Grid lines: one set defined by the columns that run in the direction of block progression, and another orthogonal set defined by rows. Block progression is a writing-mode term that defines a logical direction. In English it means vertical.
A Grid track is a generic term for a column or row which separates two Grid lines. Each Grid track is assigned a sizing function, which controls how wide or tall the column or row may grow, and thus how far apart two Grid lines are. The sizing function specified can be a length, a percentage of the Grid element’s size, derived from the contents occupying the column or row, or a proportion of the space which remains in the Grid element. In the last case, remaining space refers to the width or height of the Grid element after accounting for space already consumed by columns and rows sized with a length, percentage or content. The size can also be specified as a range using a minmax function, which can combine any of the previously mentioned mechanisms to define a min and max size for the column or row.
In the following example there are two columns and three rows. The first column is 150px wide beginning from the starting edge of the Grid element’s content box. The second column uses fractional sizing, which is a function of the remaining space in the Grid. Its size will vary as the width of the Grid element changes. If the used width of the Grid element is 200px, then the second column 50px wide. If the used width of the Grid element is 100px, then the second column is 0px and any content positioned in the column will be overflowing the Grid element. Sizing occurs in a similar fashion for the rows.
<style type="text/css"> #grid { display: grid; grid-columns: 150px 1fr; grid-rows: 50px 1fr 50px } </style>
Named Grid Lines.
A Grid line exists on either side of
a column or row. The Grid line may be
named using one or more quoted strings which are positioned in the
‘grid-rows
’ or ‘grid-columns
’
definitions where the Grid line would
logically occur (in between the sizing functions that define the Grid's
columns and rows). Each name associated with a Grid line must be unique for the set of
columns or rows. If the name is specified multiple times in the same
column or row definition, it is associated with the first Grid line to which the name was assigned.
When a name is not specified, Grid lines
can be referred to in the order which they occur. The first line is 1,
the second 2 and so on. The next example builds on the prior by
assigning each line one or more names.
<style type="text/css"> #grid { display: grid; grid-columns: "first" "nav" 150px "main" 1fr "last"; grid-rows: "first" "header" 50px "main" 1fr "footer" 50px "last"; } </style>
In addition to any explicitly named Grid lines defined by the author, a Grid element also has four implicitly defined Grid lines: a start and end line for both columns and rows. The start line is always positioned on the starting edge of the Grid element’s content box. The end line is positioned at the ending edge of the Grid element’s content box, or at the same location as the last explicitly or implicitly defined Grid line when it extends past the content box of the Grid element.
In the following example, the ‘end
’ column Grid
line is positioned on the ending edge of the Grid element’s content box. The
‘end
’ row Grid line is positioned past the ending
edge in overflow at the same location as the Grid line named "last."
<style type="text/css"> #grid { display: grid; width: auto; height: 500px; grid-columns: 50px 1fr; grid-rows: "first" 250px 250px 250px "last"; } #item { /* cover explicitly defined columns and rows */ grid-column: 1 3; grid-row: "first" "last"; /* equivalent (assuming no implicitly created tracks) */ grid-column: start end; grid-row: start end; } </style>
If there are large number of columns or rows that are the same or exhibit a recurring pattern, a repeat syntax can be applied to define the columns or rows in a more compact form.
The next two examples are equivalent. There is a single row, and a pattern of repetitive column Grid lines: a 250px column followed by a 10px gutter. Note that when repeat syntax is used with Grid line naming, that the names are assigned to the first occurrence of the pattern.
<style type="text/css"> #grid { display: grid; grid-columns: 10px "content" 250px 10px 250px 10px 250px 10px 250px 10px; grid-rows: 1fr; } /* Equivalent definition. */ #grid { display: grid; grid-columns: 10px ("content" 250px 10px)[4]; grid-rows: 1fr; } </style>
Consider not allowing named lines in the repeat syntax.
The following grammar expresses the allowable values for the
‘grid-rows
’ and ‘grid-columns
’
properties.
<track-list> => [ [ <string> ]* <track-group> [ <string> ]* ]+ | 'none' <track-group> => [ '(' [ [ <string> ]* <track-minmax> [ <string> ]* ]+ ')' [ '[' <positive-integer> ']' ]? | <track-minmax> <track-minmax> => 'minmax(' <track-breadth> ',' <track-breadth> ')' | 'auto' | <track-breadth> | 'fit-content' <track-breadth> => <length> | <percentage> | <fraction> | 'min-content' | 'max-content'
Whitespace must not occur between the closing parenthesis and the
opening square bracket of the repeat count. Whitespace must occur
between any consecutive <track-group>
and
<track-minmax>
. In all other areas, whitespace may
optionally occur.
Where:
fr
’. Each
‘fraction
’ value takes a share of the
remaining space proportional to its number. See fraction values for more details.
min
’ and less than or equal to ‘max
’. If ‘max
’ < ‘min
’, then ‘max
’ is ignored and ‘minmax(min,max)
’ is treated as ‘minmax(min,min)
’.
minmax(min-content, max-content)
’.
fit-content
’.
Consider whether having undefined behavior for percentage-sized tracks in content-sized grids is appropriate. CSS2.1 and CSS3 leave percentage width undefined, although there appears to be consistency between browser implementations.
Name: | grid-columns |
Value: | see grammar above |
Initial: | none |
Applies to: | non-replaced elements with a computed value of ‘grid ’ or ‘inline-grid ’ for
display.
|
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | see text |
Name: | grid-rows |
Value: | see grammar above |
Initial: | none |
Applies to: | non-replaced elements with a computed value of ‘grid ’ or ‘inline-grid ’ for
display.
|
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | see text |
The following example:
start
’ of the grid.
div { grid-columns: 100px 1fr max-content minmax(min-content, 1fr) }
Additional examples of valid Grid track definitions:
/* examples of valid track definitions */ grid-rows: 1fr minmax(min-content, 1fr); grid-rows: 10px (1fr auto minmax(30%, 1fr))[2]; grid-rows: (10px); grid-rows: calc(4em - 5px)
fr
’Fraction values are new units applicable
to the ‘grid-rows
’ and ‘grid-columns
’
properties:
The distribution of fractional space occurs after all ‘length
’ or content-based
row and column sizes have reached their maximum. The total size of the
rows or columns is then subtracted from the available space and the
remainder is divided proportionately among the fractional rows and
columns.
Each column or row's proportional share can be computed as the column
or row's <fraction> * <remaining space> / <sum of
all fractions>
. Note that fractions occurring within a
‘minmax
’ function are only counted in
the sum if in the ‘max
’ position.
Further, fractions that occur in the ‘min
’ position are treated as an absolute length
of 0px
.
When remaining space cannot be determined because the width or height
of the Grid element is undefined,
fraction-sized Grid tracks are sized to
their contents while retaining their respective proportions. In such
cases the size of each fractional Grid
track can be computed by determining the ‘max-content
’
size of each fractional Grid track and
dividing that size by the respective ‘fraction
’. The maximum value of those
results is treated as the 1fr
value, which is then
multiplied by each Grid track’s
‘fraction
’ to determine its final size.
The computed size of all Grid tracks
as returned for the ‘grid-rows
’ and ‘grid-columns
’
properties are normalized to used pixel values. All Grid tracks are included in the computed
value reported for ‘grid-rows
’ and ‘grid-columns
’
regardless of how the Grid tracks were
created, e.g. implicit tracks may be created by Grid items referencing a Grid line not explicitly defined by a
‘grid-rows
’ or ‘grid-columns
’
property. The computed value includes any used values for named lines;
any duplicate names must be removed. User agents may use the repeat
syntax to avoid expansive string length due to implicit Grid track creation, large spanning values
or high repeat counts specified by the author.
The algorithm used to apply repeat syntax to used Grid track values and Grid line names is user agent specific. See below for example inputs and outputs.
<style type="text/css"> #grid { width: 500px; grid-columns: "a" auto "b" minmax(min-content, 1fr) "b" "c" "d" ("e" 40px)[2] (auto)[5]; } </style> <div id="grid"> <div style="grid-column:1; width:50px"></div> <div style="grid-column:9; width:50px"></div> </div> <script type="text/javascript"> // Returns '"a" 50px "b" 320px "c" "d" ("e" 40px)[2] (0px)[4] 50px'. var gridElement = document.getElementById("grid"); window.getComputedStyle(gridElement, null).getPropertyValue("grid-columns"); </script>
The properties ‘grid-row
’ and ‘grid-column
’
are used to place Grid items in the Grid.
Name: | grid-column |
Value: | [ [ <integer> | <string> | start ] [ <integer> | <string> | end ]? ] | auto |
Initial: | auto |
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | see text |
Name: | grid-row |
Value: | [ [ <integer> | <string> | start ] [ <integer> | <string> | end ]? ] | auto |
Initial: | auto |
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | see text |
‘grid-row
’ and ‘grid-column
’
properties that refer to an undefined Grid
line will compute to their initial values.
Each Grid item is contained by a Grid cell, i.e. the Grid cell serves as the containing
block for the Grid item. The dimensions
of an anonymous Grid cell are
determined by naming the starting and ending Grid lines using the ‘grid-row
’ and
‘grid-column
’ properties on the Grid item which the Grid cell surrounds. The starting
and ending lines may be referred to by a string name, if one was defined
by the author, the start and end line keywords, or the Grid line’s number.
The following example positions the first Grid item to cover all rows and columns of
the Grid element using the start and end keywords. The second Grid item is positioned to cover the first
row. Note that when only the starting Grid
line of the ‘grid-row
’ or ‘grid-column
’
properties are specified for the Grid
cell, that the Grid cell
is assumed to extend to the subsequent Grid
line.
<style type="text/css"> /* covers the Grid element’s content box */ #item1 { grid-row: start end; grid-column: start end; } /* covers the first row */ #item2 { grid-row: start; /* extends to row Grid Line 2 */ grid-column: start end; } </style>
The next example defines rows for header and footer Grid items sized to content, as well as a main region that receives all remaining space. A single column which receives all horizontal space in the Grid's content box is also defined.
<style type="text/css"> #grid { display: grid; grid-rows: "header" auto "main" 1fr "footer" auto; grid-columns: 1fr; } #header { grid-row: "header"; grid-column: start } #main { grid-row: "main"; grid-column: start } #footer { grid-row: "footer"; grid-column: start } /* Equivalent to the above using grid line numbers instead of names. */ #header { grid-row: 1; grid-column: 1 } #main { grid-row: 2; grid-column: 1 } #footer { grid-row: 3; grid-column: 1 } </style>
Grid cells can also be
defined explicitly using one-letter names via the ‘grid-template
’ property. The ‘grid-template
’ property provides a
visualization of the Grid
element’s structure while simultaneously defining the Grid cells which can be used to
position and size the child elements of the Grid.
In the following example, a ‘grid-template
’ property is used to
create a page layout where cells are defined for header content
h
, navigational content n
, footer content
f
, and main content m
. In English, a row is
created for every separate string listed for the ‘grid-template
’ property, and a column is
created for the maximum number of letters found in any one string. In
orthogonal writing modes the roles of rows and columns are reversed. See
Grid Writing Modes for more details.
The ‘grid-cell
’ property is specified on Grid items to position the Grid item inside the explicitly named Grid cell.
<style type="text/css"> #grid { display: grid; grid-template: "hh" "nm" "ff" } #grid > a { display:block; /* make anchor tags valid Grid Items */ grid-cell: "n"; } </style>
Name: | grid-template |
Value: | <string>+ | none |
Initial: | none |
Applies to: | Grid elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
Name: | grid-cell |
Value: | <string> | none |
Initial: | none |
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
As an alternative to specifying an ending line for a Grid cell or Grid item, ‘grid-row-span
’ and ‘grid-column-span
’ properties are
available to specify a distance (line count) from the starting line to
the ending line to define the dimensions of a Grid cell. Note that when ‘grid-column-span
’ and a ‘grid-column
’
ending line are both specified for a Grid
item, that the ending line has priority. In such cases the
computed value of ‘grid-column-span
’ will be the Grid line number of the specified column
ending line minus the Grid line number
of the specified column starting line. The same holds true for the
related row properties.
<style type="text/css"> #item { /* the following two property definitions are equivalent */ /* both place the item between the first and third line */ /* which is covering the first and second row of the Grid */ grid-row: 1 3; grid-row: 1; grid-row-span: 2; } </style>
Name: | grid-column-span |
Value: | <integer> |
Initial: | 1 |
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
Name: | grid-row-span |
Value: | <integer> |
Initial: | 1 |
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
A Grid with an implicit row and two implicit columns.
Grid line numbers referred to by
‘grid-row
’ or ‘grid-column
’
properties on a Grid item are not
required to refer to a Grid line that
was defined using the ‘grid-columns
’ or ‘grid-rows
’
properties on the Grid element. In
cases where the specified position is outside those explicitly specified
on the Grid element, implicit columns
and rows fill gaps added as needed to create additional Grid lines until the reference can be
resolved. Note that quoted Grid line
names that don't resolve to an explicitly defined Grid line are treated as though the author
specified the ‘start
’ Grid
line and don't trigger implicit Grid
track creation.
Figure 10 illustrates the placement of Grid
items resulting from the markup shown in the following example.
Note that Grid item B
is
positioned on Grid line 5 which creates
a 5th column to contain Grid item
B
. Further, columns 3 and 4 are created as implicit
auto-width columns without content resulting in a used column width of
0px.
<style type="text/css"> #grid { display: grid; grid-columns: 20px; grid-rows: 20px } #A { grid-column: 1; grid-row: 1; grid-column-align: start; grid-row-align: start } #B { grid-column: 5; grid-row: 1; grid-row-span: 2; } #C { grid-column: 1; grid-row: 2; grid-column-span: 2; } </style> <div id="grid"> <div id="A">A</div> <div id="B">B</div> <div id="C">C</div> </div>
By default, any implicit columns or rows created are auto sized to
content. The default size can be changed using the ‘grid-column-sizing
’ and ‘grid-row-sizing
’ properties. The
properties accept any valid single column or row sizing function.
Name: | grid-column-sizing |
Value: | <track-minmax> (see Grid Columns and Grid Rows Properties) |
Initial: | auto |
Applies to: | Grid elements |
Inherited: | no |
Percentages: | see Grid Columns and Grid Rows Properties |
Media: | visual, paged |
Computed value: | see Computed Values for Grid-rows and Grid-columns |
Name: | grid-row-sizing |
Value: | <track-minmax> (see Grid Columns and Grid Rows Properties) |
Initial: | auto |
Applies to: | Grid elements |
Inherited: | no |
Percentages: | see Grid Columns and Grid Rows Properties |
Media: | visual, paged |
Computed value: | see Computed Values for Grid-rows and Grid-columns |
Grid items can be automatically
placed into an unoccupied space of the Grid. The ‘grid-flow
’
property controls the direction in which the search for unoccupied space
takes place, and whether rows or columns are added as needed to
accomodate the content. Note that Grid
cells cannot be automatically placed.
A ‘grid-flow
’ value of ‘rows
’ will search across
columns and then rows for unoccupied space, and will create additional
rows as needed to accomodate content. Similarly, a ‘grid-flow
’ value
of ‘columns
’
searches rows first and creates additional columns as needed until
sufficient space is found.
Name: | grid-flow |
Value: | none | rows | columns |
Initial: | none |
Applies to: | Grid elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
A form arranged using automatic placement.
The search for unoccupied space is conducted one Grid item at a time. First Grid items which have a constraint on
either their ‘grid-row
’ or ‘grid-column
’
are placed, followed by Grid items which
have both a ‘grid-row
’ and ‘grid-column
’
value of ‘auto
’. If ‘grid-flow
’ is ‘rows
’, Grid items having an ‘auto
’ value
for ‘grid-row
’ are placed before those with
an auto value for ‘grid-column
’. The reverse is true when
‘grid-flow
’ is ‘columns
’ .
In the following example, there are three columns, each auto-sized to
their contents. No rows are explicitly defined. The ‘grid-flow
’
property is ‘rows
’ which instructs the grid to search
across its three columns starting with the first row, then the next,
adding rows as needed until sufficient space is located to accomodate
the position of any auto-placed Grid
item. Figure 11 illustrates the result.
<style type="text/css"> form { display: grid; grid-columns: "labels" auto "controls" auto "oversized" auto; grid-flow: rows } form > * { /* Ensure that children of the grid are all valid grid items by setting */ /* display to 'block'. */ display: block; } form > input, form > select { /* Place all controls in the "controls" column and automatically find the */ /* next available row. */ grid-column: "controls"; grid-row: auto } form > label { /* Place all labels in the "labels" column and automatically find the next /* available row. */ grid-column: "labels"; grid-row: auto } #department { /* Auto place this item in the "oversized" column in the first row where a cell that */ /* spans three rows won't overlap other explicitly placed items or cells or any items */ /* automatically placed prior to this cell. */ grid-column: "oversized"; grid-row: auto; grid-row-span: 3; } /* Place all the buttons of the form in the explicitly defined grid cell. */ #buttons { grid-row: auto; /* Ensure the button cell spans the entire grid element in the column direction. */ grid-column: start end; grid-column-align: end } </style> <form action="#"> <label for="firstname">First name:</label> <input type="text" id="firstname" name="firstname" /> <label for="lastname">Last name:</label> <input type="text" id="lastname" name="lastname" /> <label for="address">Address:</label> <input type="text" id="address" name="address" /> <label for="address2">Address 2:</label> <input type="text" id="address2" name="address2" /> <label for="city">City:</label> <input type="text" id="city" name="city" /> <label for="state">State:</label> <select type="text" id="state" name="state"> <option value="WA">Washington</option> </select> <label for="zip">Zip:</label> <input type="text" id="zip" name="zip" /> <div id="department"> <label for="department">Department:</label> <select id="department" name="department" multiple> <option value="finance">Finance</option> <option value="humanresources">Human Resources</option> <option value="marketing">Marketing</option> <option value="payroll">Payroll</option> <option value="shipping">Shipping</option> </select> </div> <div id="buttons"> <button id="cancel">Cancel</button> <button id="back">Back</button> <button id="next">Next</button> </div> </form>
The following summarizes the algorithm for auto placement of Grid items. For each Grid item in source order:
grid-row
’ and ‘grid-column
’
are not ‘auto
’ the Grid
item is placed as specified:
grid-row
’ is not ‘auto
’,
the Grid item is placed between the
starting and ending lines specified by the ‘grid-row
’
property. An implicit Grid line
number is assigned as the starting line for ‘grid-column
’ such that the Grid item does not overlap Grid items already placed in the Grid.
If necessary, new column Grid lines
are created to satisfy this constraint.
grid-column
’ is not ‘auto
’,
the Grid item is placed between the
starting and ending lines specified by the ‘grid-column
’ property. An implicit
Grid line number is assigned as the
starting line for ‘grid-row
’ such that the Grid item does not overlap Grid items already placed in the Grid.
If necessary, new row Grid lines are
created to satisfy this constraint.
grid-column
’ and ‘grid-row
’ are
‘auto
’, beginning with the implicit Grid line numbers of the previously
placed Grid item, or (1, 1) if this is
the first Grid item to be
automatically placed:
grid-row
’ and ‘grid-column
’ auto position if not
already occupied by another Grid
item.
rows
’, increment the ‘grid-column
’. If the ‘grid-column
’ value is outside of
bounds of the grid (as defined at this point, explicitly or by
previously placed items), set ‘grid-column
’ to one and increment
‘grid-row
’ (creating new row Grid lines as needed).
columns
’, increment ‘grid-row
’.
If the ‘grid-row
’ value is outside of
bounds of the grid (as defined at this point, explicitly or by
previously placed items), set ‘grid-row
’ to one and increment
‘grid-column
’ (creating new column
Grid lines as needed).
Latin-based language row and column orientation.
Arabic language row and column orientation.
East Asian language row and column orientation.
A Grid item’s alignment within
its Cell can be controlled by using the ‘grid-column-align
’ and ‘grid-row-align
’ properties. Alignment
refers to the logical edges of the Grid
item’s Cell.
The ‘start
’ edge of a column is defined by the text
flow direction. The ‘start
’ edge of a row is defined by block flow
direction. The alignment values refer to the edge of the Grid item’s Cell against which the Grid item will align one of its edges. Which
edge of the Grid item actually aligns
against the specified edge of the Cell is dependent on whether the Grid item shares the same inline text
direction and block flow direction as the Grid
element. All descriptions below assume that the Grid item shares the same inline text
direction and block flow direction as the Grid
element. Refer to the CSS Writing Modes
Module Level 3 for more details about the relationship between parent
and child elements with differing writing-modes, and for the definitions
of inline direction and block flow direction.
Figures 12, 13, and 14 illustrate the placement and orientation of the Grid element’s rows, columns, and Grid items using different writing modes on the Grid element. In each of the figures, the markup shown in the following example is used to place Grid item A in column 1, row 1, and Grid item B in column 2, row 2. Grid item A is aligned in each figure to the starting edges of its row and column. Grid item B is aligned in each figure to the ending edges of its row and column.
<style type="text/css"> #grid { display: grid; grid-columns: 1fr 1fr; grid-rows: 1fr 1fr } #A { grid-column: 1; grid-row: 1; grid-column-align: start; grid-row-align: start } #B { grid-column: 2; grid-row: 2; grid-column-align: end; grid-row-align: end } </style> <div id="grid"> <div id="A">A</div> <div id="B">B</div> </div>
Name: | grid-column-align |
Value: | start | end | center | stretch |
Initial: | ‘stretch ’
|
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
start
’ aligns the starting edge of the Grid item’s margin box to the
starting edge of the Grid item’s
column.
end
’ aligns the end edge of the Grid item’s margin box to the end
edge of the Grid item’s column.
center
’ places the center of the Grid item’s margin box at the center
of the the Grid item’s column.
stretch
’ ensures that the Grid item’s margin box is equal to
the size of the Grid item’s
column.
Name: | grid-row-align |
Value: | start | end | center | stretch |
Initial: | ‘stretch ’
|
Applies to: | Grid Item elements |
Inherited: | no |
Percentages: | n/a |
Media: | visual, paged |
Computed value: | specified value |
start
’ aligns the starting edge of the Grid item’s margin box to the
starting edge of the Grid item’s
row.
end
’
aligns the end edge of the Grid
item’s margin box to the end edge of the Grid item’s row.
center
’ places the center of the Grid item’s margin box at the center
of the the Grid item’s row.
stretch
’ ensures that the Grid item’s margin box is equal to
the size of the Grid item’s row.
The values ‘start
’, ‘end
’, and ‘center
’ all
cause the Grid item to produce a box
sized shrink-to-fit for its cell in accordance with the CSS3 Box Model.
Note that percentage lengths specified on a Grid
item resolve against the dimensions of the Grid cell (i.e. the Grid cell serves as the containing
block for the Grid item). Percentages
specified for margin-top, padding-top, margin-bottom, and padding-bottom
resolve against the height of the grid cell, rather than the width of
the grid cell. If the ‘min-content
’ size of the Grid item’s box is greater than the
size of its Cell, it will overflow the bounds of its Cell in a direction
determined by its alignment.
A value of ‘stretch
’ causes the Grid item’s width to shrink or grow
in accordance with the equation for calculating containing block width
described in section
9.3 of the CSS3 Box Model. Note that this calculation is symmetric
for both the width and height of the Grid
item.
Drawing order controlled by z-index and source order.
Grid items do not directly affect each other's placement in the Grid element. A Grid item may affect the position of a Grid line in a column or row that uses a contents-based relative size, which in turn affects the position or size of another Grid item, but there is no direct interaction between Grid items. Grid items may overlap because the Grid item’s Cell is defined to intersect with the Cell of another Grid item. Grid item boxes in non-intersecting Cells may also overlap because of negative margins.
In cases where boxes overlap, ‘z-index
’ provides control over the
drawing order of Grid items. Both Grid elements and Grid items generate a stacking context as
described for floats (step 5, section 14) in the CSS3 Box
Model.
Figure 15 illustrates the drawing order of the markup shown in the following example.
<style type="text/css"> #grid { display: grid; grid-columns: 1fr 1fr; grid-rows: 1fr 1fr } #A { grid-column: 1; grid-row: 2; grid-column-span: 2; grid-row-align: end } #B { grid-column: 1; grid-row: 1; z-index: 10 } #C { grid-column: 2; grid-row: 1; grid-row-align: start; margin-left: -20px } #D { grid-column: 2; grid-row: 2; grid-column-align: end; grid-row-align: start } #E { grid-column: 1; grid-row: 1; grid-column-span: 2; grid-row-span: 2; z-index: 5; grid-column-align: center; grid-row-align: center } </style> <div id="grid"> <div id="A">A</div> <div id="B">B</div> <div id="C">C</div> <div id="D">D</div> <div id="E">E</div> </div>
This is the core Grid track sizing algorithm. It is run for Grid columns and Grid rows. The goal of the function is to ensure:
For the purposes of resolving the breadth that satisfies the MinTrackSizingFunction and MaxTrackSizingFunction, each Grid track falls into one of three categories:
The breadths which satisfy MinTrackSizingFunctions and MaxTrackSizingFunctions for the first category of Grid tracks are resolved in step 1 during Grid track variable initialization. The breadths which satisfy the MinTrackSizingFunctions and the MaxTrackSizingFunctions for the second category of content-sized Grid tracks are resolved in step 2. At the end of step 2, the first goal of ComputeUsedBreadthOfGridTracks function has been satisfied: the UsedBreadth variable of each GridTrack now satisfies its MinTrackSizingFunction. The MaxBreadth variable for each Grid track now contains the resolved value for its MaxTrackSizingFunction.
In step 3, the second goal of this function is satisified as each (non-fraction-sized) Grid track attempts to grow from the UsedBreadth value to the MaxBreadth value, subject to RemainingSpace.
Finally in step 4, the third category of fraction-sized Grid tracks can be resolved using what is now the RemainingSpace having updated the UsedBreadth of each Grid track at the end of step 3.
The purpose of this function is to resolve the contribution that each Grid item makes to any min-content or max-content TrackSizingFunctions for the Grid tracks it covers. There are four permutations: min-content or max-content in either the MinTrackSizingFunction or MaxTrackSizingFunction. MinTrackSizingFunctions are resolved before MaxTrackSizingFunctions, and min-content contributions are resolved before max-content contributions. Note that when resolving min-content contributions they may grow tracks that have either min-content or max-content keywords, as seen in 3.a.i and 3.b.i below.
Currently this algorithm embodies several heuristics which regulate the growth of spanning Grid items to accomodate certain use cases. (E.g. the game example in Figures 2 and 3 above.) These heuristics should be a normative part of this specification to ensure interoperability. To the extent additional use cases can be identified that cannot be satisfied by following the current heuristics, the normative algorithm can be updated, or additional mechanisms can be introduced for fine-grained control of content-based TrackSizingFunction.
The above function, ResolveContentBasedTrackSizingFunctions, groups Grid items based on the number of Grid tracks each Grid item spanned. ResolveContentBasedTrackSizingFunctionsForItems, below, then calls DistributeSpaceToTracks for each Grid item in the group to determine how much each Grid item needs to grow the Grid tracks that it covers. The maximum contribution made by any Grid item is accumulated into a temporary, per-Grid track variable, and at the end of the group, the space is recorded into a final Grid track variable as determined by the Accumulator function.
Ensures that for each Grid track in RecipientTracks, a value will be computed, UpdatedTrackBreadth, that represents the Grid track’s share of SpaceToDistribute.
There are two parts to this function. The first for loop in step 2 is giving each Grid track an equal share of the space, but without exceeding their TrackGrowthConstraint values. Because there are different MaxBreadths assigned to the different Grid tracks, the first loop can result in their uneven growth.
If the first loop completes having grown every Grid track to its TrackGrowthConstraint, and there is still SpaceToDistribute, then SubsetOfTracksForGrowthBeyondTrackGrowthConstraint are further grown equally until SpaceToDistribute is exhausted.
Note that Grid tracks considered by this function may have a TrackGrowthConstraint equal to Infinity, which signals that these tracks have not yet been grown by a Grid item. These tracks can therefore be grown without exceeding the TrackGrowthConstraint of the track. By only growing tracks up to their TrackGrowthConstraint value, we can ensure that the grid remains "tight" - that is, that track breadth is as close to the content size of the Grid items inside as possible. Only once all Grid tracks have a CurrentBreadth equal to a TrackGrowthConstraint do we move to the second for loop and grow tracks further, thereby making the Grid element less tight.
1fr
’
value, referred to as the NormalizedFractionBreadth, for a set of Grid tracks. The value computed will
ensure that when the NormalizedFractionBreadth is multiplied by the
fractions associated with GridTracks, that the UsedBreadths of
GridTracks will increase by an amount equal to the maximum of zero and
the specified SpaceToFill less the sum of the current UsedBreadths.
start
’ is only applicable to the starting
line position and ‘end
’ is only applicable to the ending line
position.
This specification is made possible by input from Erik Anderson, Rossen Atanassov, Arron Eicholz, Sylvain Galineau, John Jansen, Chris Jones, Kathy Kam, Veljko Miljanic, Peter Salas, Christian Stockwell, Eugene Veselov, and the CSS Working Group members. Thanks to Eliot Graff for editorial input.
Property | Values | Initial | Applies to | Inh. | Percentages | Media |
---|---|---|---|---|---|---|
display | [ ...existing values... | grid | inline-grid | | specified value | ||||
grid-cell | <string> | none | none | Grid Item elements | no | n/a | visual, paged |
grid-column | [ [ <integer> | <string> | start ] [ <integer> | <string> | end ]? ] | auto | auto | Grid Item elements | no | n/a | visual, paged |
grid-column-align | start | end | center | stretch | ‘stretch’ | Grid Item elements | no | n/a | visual, paged |
grid-columns | see grammar above | none | non-replaced elements with a computed value of ‘grid’ or ‘inline-grid’ for display. | no | n/a | visual, paged |
grid-column-sizing | <track-minmax> (see Grid Columns and Grid Rows Properties) | auto | Grid elements | no | see Grid Columns and Grid Rows Properties | visual, paged |
grid-column-span | <integer> | 1 | Grid Item elements | no | n/a | visual, paged |
grid-flow | none | rows | columns | none | Grid elements | no | n/a | visual, paged |
grid-row | [ [ <integer> | <string> | start ] [ <integer> | <string> | end ]? ] | auto | auto | Grid Item elements | no | n/a | visual, paged |
grid-row-align | start | end | center | stretch | ‘stretch’ | Grid Item elements | no | n/a | visual, paged |
grid-rows | see grammar above | none | non-replaced elements with a computed value of ‘grid’ or ‘inline-grid’ for display. | no | n/a | visual, paged |
grid-row-sizing | <track-minmax> (see Grid Columns and Grid Rows Properties) | auto | Grid elements | no | see Grid Columns and Grid Rows Properties | visual, paged |
grid-row-span | <integer> | 1 | Grid Item elements | no | n/a | visual, paged |
grid-template | <string>+ | none | none | Grid elements | no | n/a | visual, paged |