javascript多物体运动案例：多物体淡入淡出

javascript多物体运动案例：多物体淡入淡出

任务描述：

补充代码，当鼠标移入红色区域时，该区域透明度逐渐增加至不透明;当鼠标移出该红色区域时，该区域透明度逐渐恢复至初始程度。

效果图：

<!DOCTYPE html>
<html>

<head lang="zh-CN">
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1,maximum-scale=1,user-scalable=no">
    <title>多个div淡入淡出</title>
    <style>
        div {
            width: 200px;
            height: 200px;
            margin: 20px;
            float: left;
            background: red;
            filter: alpha(opacity=30);
            opacity: 0.3;
        }

    </style>
</head>

<body>
    <div></div>
    <div></div>
    <div></div>
    <div></div>
  
    <script type="text/javascript">
      //补充代码

    </script>
</body>

</html>

　　

参考代码：

aDiv = document.getElementsByTagName('div');

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)

}

　　

　　

posted @ 2019-08-09 11:09  请叫我二狗哥  阅读(189)  评论(0)    收藏  举报