var oMarquee = document.getElementById("gundong"); //滚动对象 
var iLineHeight = 100; //单行高度，像素 
var iLineCount = 5; //实际行数 
var iScrollAmount = 1; //每次滚动高度，像素 
function run() {
    oMarquee.scrollTop += iScrollAmount;
    if (oMarquee.scrollTop == iLineCount * iLineHeight) oMarquee.scrollTop = 0;
    if (oMarquee.scrollTop % iLineHeight == 0) {
        window.setTimeout("run()", 2500);
    } else {
        window.setTimeout("run()", 10);
    }
}
oMarquee.innerHTML += oMarquee.innerHTML;
window.setTimeout("run()", 2500);