54 lines
1.6 KiB
HTML
54 lines
1.6 KiB
HTML
<!DOCTYPE html>
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<html lang="en">
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<head>
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<meta charset="UTF-8">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<meta http-equiv="X-UA-Compatible" content="ie=edge">
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<title>Document</title>
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<style>
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/* 使用通配符浪费性能，尽量不使用 */
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* {
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margin: 0;
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padding: 0;
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}
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div {
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width:400px;
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height:400px;
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background-color: #000;
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color: #ffffff;
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margin: 50px;
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position: relative;
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}
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div span {
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position: absolute;
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left: 0;
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top: 0;
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}
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</style>
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</head>
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<body>
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<input type="button" value="星星点点" id="btn">
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<div id="dv">
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<!-- 可以做一个好看的星星，方便操作 -->
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<!-- <span>※</span> -->
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</div>
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<script type="text/javascript">
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document.getElementById('btn').onclick = function() {
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// 定义'dv'，优化性能
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var dv = document.getElementById('dv');
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//每隔一段时间添加一次
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//创建定时器
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setInterval(function() {
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//动态的向div内添加一颗星星
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dv.innerHTML = "<span>※</span>"
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//每间隔一段时间随机生成坐标 [0,400]
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var numX = parseInt(Math.random()*401);
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var numY = parseInt(Math.random()*401);
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dv.firstElementChild.style.left = numX + 'px';
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dv.firstElementChild.style.top = numY + 'px';
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}, 10)
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}
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</script>
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</body>
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</html> |