$(window).load(function(){
  
 var counter = 0;
 var totalSlide = $('.slider_container img').length;
 $('.slider_container').css('width', totalSlide*960);
  
 setInterval(function(){
 
   var left = counter*(-1)*960;
   $('.slider_container').animate({
     marginLeft: left
   }, 500);
   
   if(counter == totalSlide-1){
     counter = 0;  
   }
   else{
     ++counter;
   }
   }, 4000);
  
});