 
<!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> 
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" /> 
<title>勻速運(yùn)動(dòng)演示</title> 
<style type="text/css"> 
<!-- 

#div1 {width:1px;height:200px;background-color: black;position:absolute;left:100px;top:70px;float:left} 
#div1 span {position:absolute;top:-15px} 
#div2 {width:1px;height:200px;background-color:midnightblue;position:absolute;left:800px;top:70px;float: left} 
#div2 span {position:absolute;top:-15px} 
#div3 {width:1px;height:200px;background-color:fuchsia;position:absolute;left:300px;top:70px;float: left} 
#div3 span {position:absolute;top:-15px} 
#div4 {width:1px;height:200px;background-color:darkmagenta;position:absolute;left:500px;top:70px;float: left} 
#div4 span {position:absolute;top:-15px} 
#grap {width:200px;height:200px;background:red;position:absolute;left:300px;top:74px;float: left;} 
input {width:100px;margin-left: 90px;} 
--> 
</style> 
<script type="text/javascript"> 
var timeId 
function startMove(target){ 
var oDiv=document.getElementById('grap') 
clearInterval(timeId); //這個(gè)地方就是為了防止多次點(diǎn)擊速度加快的現(xiàn)象，很重要 
speed=oDiv.offsetLeft<target?8:-9; 
timeId=setInterval(function(){ 
if(Math.abs(oDiv.offsetLeft-target)<=6){ 
oDiv.style.left=target+'px'; //只要矩形移動(dòng)到接近到目標(biāo)點(diǎn)處就直接移動(dòng)到目標(biāo)點(diǎn)上，肉眼無(wú)法察覺(jué)速度變化 
clearInterval(timeId); document.title="目標(biāo)"+oDiv.style.left; 
} 
else{ 
oDiv.style.left=oDiv.offsetLeft+speed+'px'; 
} 
},30); 
} 
</script> 
</head> 
<body> 
<div id="div1"><span>100px</span></div> 
<div id="div2"><span>800px</span></div> 
<div id="div3"><span>300px</span></div> 
<div id="div4"><span>500px</span></div> 
<input type="button" value="移動(dòng)到100px處" onclick="startMove(100)"/> 
<input type="button" value="移動(dòng)到300px處" onclick="startMove(300)"/> 
<input type="button" value="移動(dòng)到500px處" onclick="startMove(500)"/> 
<input type="button" value="移動(dòng)到800px處" onclick="startMove(800)"/> 
<div id="grap" ></div> 

</body> 
</html> 