// wrap as a jQuery plugin and pass jQuery in to our anoymous function
(function ($) {
   $.fn.cross = function (options) {
       return this.each(function (i) { 
           // cache the copy of jQuery(this) - the start image
           var $$ = $(this);

           // get the target from the backgroundImage + regexp
           var target = $$.css('backgroundImage').replace(/^url|[\(\)'"]/g, '');

           // nice long chain: wrap img element in span
           $$.wrap('<span style="position: relative;"></span>')
               // change selector to parent - i.e. newly created span
               .parent()
               // prepend a new image inside the span
               .prepend('<img>')
               // change the selector to the newly created image
               .find(':first-child')
               // set the image to the target
               .attr('src', target);

           // the CSS styling of the start image needs to be handled
           // differently for different browsers
           if ($.browser.mozilla) {
               $$.css({
                   'position' : 'absolute', 
                   'left' : 0,
                   'background' : '',
                   'top' : this.offsetTop
               });
           } else if ($.browser.msie && $.browser.version > 7) {
               $$.css({
                   'position' : 'absolute', 
                   'left' : 0,
                   'background' : '',
                   'top' : "-162px"
            });
           } else if ($.browser.msie || $.browser.opera && $.browser.version < 9.5) {
               // Browser sniffing is bad - however opera < 9.5 has a render bug 
               // so this is required to get around it we can't apply the 'top' : 0 
               // separately because Mozilla strips the style set originally somehow...                    
               $$.css({
                   'position' : 'absolute', 
                   'left' : 0,
                   'background' : '',
                   'top' : "0"
               });
           } else { // Safari
               $$.css({
                   'position' : 'absolute', 
                   'left' : 0,
                   'background' : ''
               });
           }

           // similar effect as single image technique, except using .animate 
           // which will handle the fading up from the right opacity for us
           $$.hover(function () {
               $$.stop().animate({
                   opacity: 0
               }, 250);
           }, function () {
               $$.stop().animate({
                   opacity: 1
               }, 250);
           });
       });
   };

})(jQuery);

// note that this uses the .bind('load') on the window object, rather than $(document).ready() 
// because .ready() fires before the images have loaded, but we need to fire *after* because
// our code relies on the dimensions of the images already in place.
$(window).bind('load', function () {
   $('img.fade').cross();
});

// JavaScript Document