<!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>
<title>碰撞运动</title>
<style>
#div1
{
width:100px;
height:100px;
background:red;
position:absolute;
}
</style>
<script type="text/javascript">
window.onload = function(){
var oBtn = document.getElementById("btn");
oBtn.onclick = function(){
move();
}
}
var timer = null;
var speedX = 6;
var speedY = 8;
function move(){
clearInterval(timer);
timer = setInterval(function(){
var oDiv = document.getElementById("div1");
var l = oDiv.offsetLeft + speedX ;
var t = oDiv.offsetTop + speedY;
if(t >= document.documentElement.clientHeight-oDiv.offsetHeight)
{
speedY*=-1;
t = document.documentElement.clientHeight - oDiv.offsetHeight;
}
else if(t<=0)
{
speedY*=-1;
t=0;
}
if(l>=document.documentElement.clientWidth-oDiv.offsetWidth)
{
speedX*=-1;
l = document.documentElement.clientWidth - oDiv.offsetWidth;
}
else if(l<=0)
{
speedX*=-1;
l = 0;
}
oDiv.style.left = l+'px';
oDiv.style.top = t +'px';
},30);
}
</script>
</head>
<body>
<input type="button" id="btn" value="运动" />
<div id="div1">
</div>
<span style="width:1px;height:300px;background:black;left:300px"></span>
</body>
</html>
