Load images as you scroll

   var scrollLoader = function(){
      return{
        elements: [],
        winHeight: window.innerHeight ? window.innerHeight : $(window).height(),
        threshHold: 150,
        init: function(){
  	      this.setElementsPosition();        
  	      $(window).bind('scroll',_.bind(scrollLoader.checkViewPort,this));
  this.checkViewPort.lastChecked = 0;
  this.checkViewPort.busy = false;
  	      this.checkViewPort();

        },
        setElementsPosition: function(){
          var els       = $('.dl');
          var me        = this;
          var scrollTop = window.scrollY + this.threshHold;

          els.each(function(i){
            var el            = $(this);
            var top           = parseInt(el.offset().top)+i;
            me.elements[top]  = el;
          });

        },
        checkViewPort: function(){
  if(this.checkViewPort.busy === true){
  return;
  }
  this.checkViewPort.busy = true;
          var scrollTop = window.scrollY + this.threshHold + this.winHeight;
          var me        = this;
if(me.elements.length == 0){
$(window).unbind('scroll');
return;
}
          for(var i = scrollTop; i > this.checkViewPort.lastChecked; i--){
            if(me.elements[i] instanceof Object){
              var img = me.elements[i].find('img');

              var a   = document.createAttribute('src');
              a.value = img.attr('rel');
              img[0].setAttributeNode(a)
              me.elements[i] = null;
            }
          }
  this.checkViewPort.lastChecked = scrollTop;
  this.checkViewPort.busy = false;

        }
      }
    }();

    scrollLoader.init();