Allow Rails web applications to make AJAX requests (with PUT/DELETE/GET/POST) in IE8 using jQuery with XDomainRequest. Also works with Backbone transport.

Originally forked from https://github.com/MoonScript/jQuery-ajaxTransport-XDomainRequest

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Implements automatic Cross Origin Resource Sharing support using the XDomainRequest object for IE8 and IE9 when using the $.ajax function in jQuery 1.5+.

CORS requires the Access-Control-Allow-Origin header to be present in the AJAX response from the server.

In order to use XDomainRequest in Internet Explorer, the request must be:

• Only GET or POST
• When POSTing, the data will always be sent with a Content-Type of text/plain
• Only HTTP or HTTPS
• Protocol must be the same scheme as the calling page
• Always asynchronous

With at least jQuery version 1.5, just include the rails-ie8.domainrequest.js inside your javascript directory and include it in your application.script into your page, then make your AJAX call like you normally would:

// GET
$.getJSON('http://jsonmoon.jsapp.us/').done(function(data) {
  console.log(data.name.first);
});

// POST
$.ajax({
  url: 'http://frozen-woodland-5503.herokuapp.com/cors.json',
  data: 'this is data being posted to the server',
  contentType: 'text/plain',
  type: 'POST',
  dataType: 'json'
}).done(function(data) {
  console.log(data.name.last);
});

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Inside your Rails application, the following steps are necessary:

Download the rack-methodoverride-with-params gem

gem 'rack-methodoverride-with-params'

Inside application.rb, include the following

  # overridewithparams to allow IE8 support ?_method= in url when posting JSON data
  config.middleware.use Rack::MethodOverrideWithParams

If using HTTP Basic-Auth (optional), place the following inside your controller

  if params['x-authorization'] # IE8 will use this to authenticate as it cannot pass custom headers
    @email, @password = ::Base64.decode64(params['x-authorization'].split(' ', 2).last ||
'').split(':') 
  end

All jQuery HTTP requests will either be GET or POSTed with _method parameters included to indicate proper VERB action transparently.