var stopscroll = false; 
var scrollElem = document.getElementById("LeftNewsCont"); 
var marqueesHeight = scrollElem.style.height; 
scrollElem.onmouseover = new Function('stopscroll = true'); 
scrollElem.onmouseout = new Function('stopscroll = false'); 
var preTop = 0; 
var currentTop = 0; 
var stoptime = 0; 
var leftElem = document.getElementById("LeftNewsMar");  
scrollElem.appendChild(leftElem.cloneNode(true)); 
init_srolltext(); 

function init_srolltext(){ 
 scrollElem.scrollTop = 0; 
 setInterval('scrollUp()', 50);//的面的这个参数25, 是确定滚动速度的, 数值越小, 速度越快 
} 
function scrollUp(){ 
 if(stopscroll) return; 
 currentTop += 2; //设为1, 可以实现间歇式的滚动; 设为2, 则是连续滚动 
 if(currentTop == 19) { 
 stoptime += 1; 
 currentTop -= 1; 
 if(stoptime == 180) { 
 currentTop = 0; 
 stoptime = 0; 
 } 
 }else{ 
 preTop = scrollElem.scrollTop; 
 scrollElem.scrollTop += 1; 
 if(preTop == scrollElem.scrollTop){ 
 scrollElem.scrollTop = 0; 
 scrollElem.scrollTop += 1; 
 } 
 } 
}