var scrollSpeed = 10;       // Speed in milliseconds
    var step = .1;               // How many pixels to move per step
    var current = 0;            // The current pixel row
    var imageHeight = 2825;     // Background image height
    var headerHeight = 322;     // How tall the header is.
   
    //The pixel row where to start a new loop
    var restartPosition = -(imageHeight - headerHeight);
   
    function scrollBg(){
       
        //Go to next pixel row.
        current -= step;
       
        //If at the end of the image, then go to the top.
        if (current == restartPosition){
            current = 0;
        }
       
        //Set the CSS of the header.
        $('#home_header').css("background-position","0 "+current+"px");
       
       
    }
   
    //Calls the scrolling function repeatedly
    var init = setInterval("scrollBg()", scrollSpeed);