<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>链式动画</title>
<style>
body,div{
margin: 0;
padding:0;
}
#div1{
width:200px;
height:100px;
background-color:yellow;
border:4px solid #000;
opacity:0.3;
}
</style>
<script>
window.onload=function(){
var oDiv =document.getElementById('div1');
oDiv.onmouseover =function(){
startMove(oDiv,'width',400,function(){
startMove(oDiv,'height',300,function(){
startMove(oDiv,'opacity',100);
});
});
};
oDiv.onmouseout = function(){
startMove(oDiv,'opacity',30,function(){
startMove(oDiv,'height',100,function(){
startMove(oDiv,'width',200);
})
})
}
}
function startMove(obj,attr,iTarget,fn){
clearInterval(obj.timer);
obj.timer = setInterval(function(){
var icur = null; // 1.属性值 变量
if(attr == 'opacity'){
icur = Math.round(parseFloat(getStyle(obj,attr))*100);
}else{
icur = parseInt(getStyle(obj,attr));
}
var speed = (iTarget - icur)/8; // 2.速度 变速
speed = speed > 0 ? Math.ceil(speed) : Math.floor(speed);
if(icur == iTarget){ // 3.判断是否暂停 变化过程
clearInterval(obj.timer);
if(fn){ //链式
fn();
}
}else{
if(attr == 'opacity'){
obj.style.opacity = (icur +speed)/100;
}else{
obj.style[attr] = icur + speed + 'px';
}
}
},30)
}
function getStyle(obj,attr){ //获取任意属性
if(obj.currentStyle){
return obj.currentStyle[attr];
}else{
return getComputedStyle(obj,false)[attr];
}
}
</script>
</head>
<body>
<div id="div1"></div>
</body>
</html>
