文字向上滚动

<div class="content_three" id="content_three">
	<div class="list_all" id="list_all"></div>
	<div class="list_all" id="list_copy"></div>
</div>

var speed = 40 ;
var content_three = document.getElementById("content_three");  
var list_copy = document.getElementById("list_copy");  
var list_all = document.getElementById("list_all");  
list_copy.innerHTML = list_all.innerHTML + list_all.innerHTML;

function Marquee() {  
    if (list_copy.offsetTop - content_three.scrollTop <= 0)  
        content_three.scrollTop -= list_all.offsetHeight ; 
    else {  
        content_three.scrollTop++ ; 
    }  
}  
var MyMar = setInterval(Marquee, speed);  
content_three.onmouseover = function() { clearInterval(MyMar)} 
content_three.onmouseout = function() { MyMar = setInterval(Marquee, speed)}