// JavaScript Document
function textScroll(textId,picTopId,picBottomId){
	function $(e) {return document.getElementById(e);}
			
	var MyMar;
	var speed = 1; //速度，越大越慢
	var spec = 1; //每次滚动的间距, 越大滚动越快

	$(picTopId).onmouseover = function() {MyMar=setInterval(gotop,speed);}
	$(picTopId).onmouseout = function() {clearInterval(MyMar);}
	$(picBottomId).onmouseover = function() {MyMar=setInterval(gobottom,speed);}
	$(picBottomId).onmouseout = function() {clearInterval(MyMar);}
	function gotop() {$(textId).scrollTop-=spec;}
	function gobottom() {$(textId).scrollTop+=spec;}
}