JavaScript 动画效果实例
分类：实例代码
本章节分享一段代码实例，它利用JavaScript实现了简单的动画效果。
代码实例如下:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="author" content="http://www.pipipi.net/" />
<title>前端教程网</title>
<style>
body{
margin:0;
padding:0;
font:12px/1.5 arial;
}
#box{
width:100px;
height:100px;
position:absolute;
background:#06c;
left:0;
filter:alpha(opacity=30);
opacity:0.3;
}
</style>
<script>
function getstyle(obj,name){
if(obj.currentStyle){
return obj.currentStyle[name];
}
else{
return getComputedStyle(obj,false)[name];
}
}
window.onload = function(){
var box = document.getElementById("box");
box.onmouseover = function(){
startrun(box,"width",200,function(){
startrun(box,"height",200,function(){
startrun(box,"opacity","100")
});
});
}
box.onmouseout = function(){
startrun(box,"height",100,function(){
startrun(box,"width",100,function(){
startrun(box,"opacity","30");
});
});
}
}
function startrun(obj,attr,target,fn){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
var cur = 0;
if(attr == "opacity"){
cur = Math.round(parseFloat(getstyle(obj,attr))*100);
}
else{
cur = parseInt(getstyle(obj,attr));
}
var speed = (target-cur)/8;
speed = speed>0?Math.ceil(speed):Math.floor(speed);
if(cur == target){
clearInterval(obj.timer);
if(fn){
fn();
}
}
else{
if(attr == "opacity"){
obj.style.filter = "alpha(opacity="+(cur+speed)+")";
obj.style.opacity = (cur+speed)/100;
}
else{
obj.style = cur + speed + "px";
}
}
},30)
}
</script>
</head>
<body>
<div id="box"></div>
</body>
</html>
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