var imagelistamount, imagelisttimer;   
function scrollimagelist(){
    imagelistamount=arguments[0];
    imagelisttimer=setInterval("stepimagelist()", arguments[1]);
}

function stepimagelist()
{
    document.getElementById("imagelist").scrollLeft+=imagelistamount;
}

function stopimagelist(){
    clearInterval(imagelisttimer);
}