问如何在div标记中自动移动滚动条？

EN

var autoscrollTimer;

function cancelscrolling()
{
    clearTimeout(autoscrollTimer);
}

function autoscroll()
{
    var gal = $(".gallery");

    // don't cancel if it is the code scrolling
    gal.off("scroll");

    gal.animate({ scrollLeft: "+=" + gal.width() },
                function() {
                    setTimeout(function(){
                        // when the animation ends re-add the code
                        // to stop scrolling if the user scrolls
                        gal.on("scroll", cancelscrolling);
                    }, 1);
                });

    // if still not in the end, continue scrolling
    if (gal.get(0).scrollWidth > (gal.get(0).scrollLeft + gal.width()))
        autoscrollTimer = setTimeout(autoscroll, 3000);
}

$(".gallery").on("scroll", cancelscrolling);

// starts the loop
autoscroll();

$(document).ready(function(){
    lastElementLeft = $('.demo').position().left ;
    scrollAmount = lastElementLeft + 200 ;
    //alert(scrollAmount);

$('.demo').animate({scrollLeft: scrollAmount},1000);
});