//rotation
function addLoadEvent(func) { 
var oldonload = window.onload; 
if (typeof window.onload != 'function') { 
    window.onload = func; 
} else { 
    window.onload = function() { 
      if (oldonload) { 
        oldonload(); 
      } 
      func(); 
    } 
} 
}

 $(function(){
  var index = 0;
  var imgUrl = [
       "images/index_pic1.jpg",
       "images/index_pic2.jpg", 
       "images/index_pic3.jpg", 
       "images/index_pic4.jpg",
       "images/index_pic5.jpg"
       ];
  $(".index").css("background-image","url(" + imgUrl[0] + ")");
  $(".index").css("margin-left", "auto");
  $(".index").css("margin-right", "auto");
  addLoadEvent(function(){
   setInterval(function(){
    index++;
    if(index > imgUrl.length-1){
     index = 0;
    };
    
    $(".index").fadeOut("slow",function(){
     $(".index").css("background-image","url(" + imgUrl[index] + ")");
     $(".index").fadeIn("slow");
    });
   },5000);
  });
 });