运动——淡入淡出

一、一个DIV设置淡入淡出

代码：

<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>运动--淡入淡出</title>

<style>
#div {
width: 200px;
height: 200px;
background: #ff2e1d;
position: absolute;
left: 100px;
top: 100px;
opacity: 0.3;
filter: alpha(opacity:30);


}

</style>
<script>
window.onload = function () {
var oDiv = document.getElementById("div");
oDiv.onmouseover = function () {
startMove(100);
};

oDiv.onmouseout = function () {
startMove(30);
};

var alpha = 30;
var timer = null;

function startMove(iTarget) {
clearInterval(timer);
timer = setInterval(function () {
var speed = 0;
if (alpha < iTarget) {
speed = 10;
} else {
speed = -10;
}

if (alpha == iTarget) {
clearInterval(timer);
} else {
alpha += speed;
oDiv.style.filter = 'alpha(opacity:' + alpha + ')';
oDiv.style.opacity = alpha / 100;
}
}, 30);

}
}

</script>
</head>
<body>
<div id="div"></div>

</body>
</html>

运行结果：

初始：

鼠标移入：

鼠标移出：

二、多个DIV设置淡入淡出

代码：

<!DOCTYPE HTML>
<html>
<head>
    <meta charset="utf-8">
    <title>无标题文档</title>
    <style>
        div {width:200px; height:200px; margin:20px; float:left; background:red; filter:alpha(opacity:30); opacity:0.3;}
    </style>
    <script>
        window.onload=function ()
        {
            var aDiv=document.getElementsByClassName("e");

            for(var i=0;i<aDiv.length;i++)
            {
                aDiv[i].alpha=30;

                aDiv[i].onmouseover=function ()
                {
                    startMove(this, 100);
                };
                aDiv[i].onmouseout=function ()
                {
                    startMove(this, 30);
                };
            }
        };


        function startMove(obj, iTarget)
        {
            clearInterval(obj.timer);
            obj.timer=setInterval(function (){
                var speed=(iTarget-obj.alpha)/6;
                speed=speed>0?Math.ceil(speed):Math.floor(speed);

                if(obj.alpha==iTarget)
                {
                    clearInterval(obj.timer);
                }
                else
                {
                    obj.alpha+=speed;

                    obj.style.filter='alpha(opacity:'+obj.alpha+')';
                    obj.style.opacity=obj.alpha/100;
                }
            }, 30);
        }
    </script>
</head>

<body>
<div class="e"></div>
<div class="e"></div>
<div class="e"></div>
<div class="e"></div>
</body>
</html>

运动——淡入淡出

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