/*
*  jQuery Dynamic Background Image Plugin
*  Requires jQuery v1.2.6 or later
* 
*  Copyright (c) Thomas Bindzus (http://bindzus.wordpress.com)
*
*  Dual licensed under the MIT and GPL licenses:
*  http://www.opensource.org/licenses/mit-license.php
*  http://www.gnu.org/licenses/gpl.html
* 
*  Version: 1.0
*/
(
   function ($) {
       $.fn.fitToBackgroundImage = function () {
           // Helper function to extract the URL from CSS
           function cleanupUrl(aUrl) {
               var regExp = /^url\("?(.*?)"?\)$/ig;
               var matches = regExp.exec(aUrl);

               if (matches == null || typeof matches[1] == "undefined")
                   return null;

               return matches[1];
           }

           // Returning the updated HTML elements in a
           // way that allows for other jQuery methods
           // to manipulate them further
           return this.each
         (
            function (index) {
                // Ensure we get a reference to the element
                // which we can use closure on
                var $this = $(this);

                // Get the baground image using jQuery,
                // no need to worry about computed style
                // because jQuery will handle that part
                var backgroundImageUrl =
                  cleanupUrl($this.css("background-image"));

                // If no background image is set then return
                if (backgroundImageUrl == null)
                    return;

                // Create a dummy image to get the dimensions 
                // of the image
                var dummyImage = document.createElement("img");

                // When the image is loaded then set the dimensions
                dummyImage.onload = function () {
                    // Thanks to JavaScript closure we can access
                    // the elt variable from the onload method
                    $this.css("width", this.width + "px")
                       .css("height", this.height + "px");
                };

                // Get the URL for the background image
                dummyImage.src = backgroundImageUrl;

                // Cleanup
                dummyImage = null;
            }
         );
       }
   }
)(jQuery);