使用jQuery的background-image预加载器

$(document).ready(function(E){

   // get a collection of all elements with a BG image
   var bgImages = $('*').filter(function(){
       return $(this).css('BACkground-image') != 'none');

   // get a collection of new images,assigning the sources from the original collection
   }).map(function() {
       return $("<img />").attr("src",$(this).css('BACkground-image').slice(5,-2));
   });

   var len = bgImages.length;
   var loadCounter = 0;

   // use an onload counter to keep track of which ones have loaded
   bgImages.load(function() {
      loadCounter++;
      if(loadCounter == len) {

         // we have all loaded
         // fade out curtain
      }
   }).each(function() {

      // if we have been pulled up from cache,manually trigger onload
      if (this.completE) $(this).trigger("load");
   });
});