本文实例讲述了JS实现的DIV块来回滚动效果。分享给大家供大家参考，具体如下：
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<div id="xx" style=" position:relative;left:100px;width:100px;height:50px;border: solid 1px red;"></div>
<script type="text/javascript">
function ls(){
var p=true;//开关,true开,false关
var xx=document.getElementById('xx');
var xxleft = parseInt(xx.style.left);
var speed = 20;
var t=setInterval(rollRight,speed);
//向左移动
function rollLeft(){
if(p){
xxleft--;
xx.style.left = xxleft+'px';
if(xxleft <=0 ){
clearInterval(t);
t=setInterval(rollRight,speed);
}
}
}
//向右移动
function rollRight(){
if(p){
xxleft++;
xx.style.left = xxleft+'px';
if(xxleft >= 300){
clearInterval(t);
t=setInterval(rollLeft,speed);
}
}
}
}
ls();
</script>
</body>
</html>
运行效果图如下：
希望本文所述对大家JavaScript程序设计有所帮助。
