<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<style>
#div1 {width:100px; height:100px; background:red; position:absolute;}
</style>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script>
var iSpeedX=;
var iSpeedY=;
function startMove()
{
setInterval(function (){
var oDiv=document.getElementById('div1');
iSpeedY+=;
var l=oDiv.offsetLeft+iSpeedX;
var t=oDiv.offsetTop+iSpeedY;
if(t>=document.documentElement.clientHeight-oDiv.offsetHeight)
{
iSpeedY*=-0.8;
iSpeedX*=0.8;
t=document.documentElement.clientHeight-oDiv.offsetHeight;
}
else if(t<=)
{
iSpeedY*=-;
iSpeedX*=0.8;
t=;
}
if(l>=document.documentElement.clientWidth-oDiv.offsetWidth)
{
iSpeedX*=-0.8;
l=document.documentElement.clientWidth-oDiv.offsetWidth;
}
else if(l<=)
{
iSpeedX*=-0.8;
l=;
}
if(Math.abs(iSpeedX)<)
{
iSpeedX=;
}
if(Math.abs(iSpeedY)<)
{
iSpeedY=;
}
oDiv.style.left=l+'px';
oDiv.style.top=t+'px';
document.title=iSpeedX;
}, );
}
</script>
</head>
<body>
<input type="button" value="开始运动" onclick="startMove()" />
<div id="div1">
</div>
</body>
</html>