js 实现简单的开关灯效果

程序员文章站 2022-05-29 20:49:53

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代码如下，难点在于position属性和z-index属性

<!DOCTYPE html>
<html>
<head>
    <title></title>
<style>
    .mask {
        position: fixed;
        top: 0px;
        left: 0px;
        width: 100%;
        height: 100%;
        background-color: black;
        opacity: 0.0;
        z-index: 100;
    }

    .player {
        position: relative;
        height: 500px;
        width: 80%;
        margin: 20px auto;
        text-align: center;
        line-height: 400px;
        font-size: 100px;
        z-index: 101;
        background: white;
    }

    .kg {
        display: block;
        font-size: 50px;
    }

    .mask-active {
        opacity: 0.9;
    }

</style>
</head>
<body>
<div class="mask mask-active"></div>

<div class="player">
    播放器
<button class="kg">开关</button>
</div>
</body>
<script>

    var log = function() {
        console.log.apply(console, arguments);
    }

    var $ = function(ele) {
        return document.querySelector(ele);
    }

    var kg = $('.kg');
    var msk = $('.mask');

    kg.addEventListener('click', function() {
        if (msk.classList.contains('mask-active')) {
            msk.classList.remove('mask-active');
        } else {
            msk.classList.add('mask-active');
        }
    })


</script>
</html>