49 lines
1.1 KiB
HTML
49 lines
1.1 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 http-equiv="X-UA-Compatible" content="IE=edge">
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<meta name="viewport" content="width=device-width, initial-scale=1.0">
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<title>Document</title>
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<style>
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body {
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height: 30000px;
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}
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.header {
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width: 100%;
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height: 100px;
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background: red;
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}
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.fixed {
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position: fixed;
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width: 100%;
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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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<div class="header"></div>
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</body>
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<script>
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var header = $(".header");
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//获取class为header的元素
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$("body").onscroll = function () {
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//定义页面的滚动事件
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if (document.documentElement.scrollTop > 400) {
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//如果页面滚动的高度大于400时
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header.className = "header fixed"
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//给元素定位通过css属性进行添加
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}else{
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header.className = "header"
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}
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}
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function $(className) {
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return document.querySelector(className)
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}
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</script>
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</html> |