CSS实现代码高亮显示行数原理解析，设计自己代码高亮

2021-11-02 网页编程网 网页编程网

CSS构建代码行数的原理如下：

使用::before伪元素content属性生成，这样不用担心网页框选复制代码的时候行数序号会污染。

使用\A控制字符的换行，之前有效果应用过此特性，见“CSS content换行技术实现字符animation loading效果”。

::before伪元素绝对定位在左侧，祖先元素设置overflow:hidden隐藏多余的行数。

<html>
<head>
<meta charset="utf-8">
<style>
.code {
    padding: 10px 10px 10px 40px;
    font-size: 13px;
    line-height: 18px;
    background-color: #eee;
    font-family: "Lucida Console", Consolas, Monaco;
    white-space: pre-wrap;
    word-break: break-all;
    position: relative;
    overflow: hidden;
}
.code::before {
    content: '01.\A 02.\A 03.\A 04.\A 05.\A 06.\A 07.\A 08.\A 09.\A 10.\A 11.\A 12.\A 13.\A 14.\A 15.\A 16.\A 17.\A 18.\A 19.\A 20.\A 21.\A 22.\A 23.\A 24.\A 25.\A 26.\A 27.\A 28.\A 29.\A 30.\A 31.\A 32.\A 33.\A 34.\A 35.\A 36.\A 37.\A 38.\A 39.\A 40.\A 41.\A 42.\A 43.\A 44.\A 45.\A 46.\A 47.\A 48.\A 49.\A 50.\A 51.\A 52.\A 53.\A 54.\A 55.\A 56.\A 57.\A 58.\A 59.\A 60.\A 61.\A 62.\A 63.\A 64.\A 65.\A 66.\A 67.\A 68.\A 69.\A 70.\A 71.\A 72.\A 73.\A 74.\A 75.\A 76.\A 77.\A 78.\A 79.\A 80.\A 81.\A 82.\A 83.\A 84.\A 85.\A 86.\A 87.\A 88.\A 89.\A 90.\A 91.\A 92.\A 93.\A 94.\A 95.\A 96.\A 97.\A 98.\A 99';
    position: absolute;
    top: 10px;
    bottom: 10px;
    left: 0;
    text-align: right;
    background-color: #fbfbfb;
    color: #333;
    outline: 100px solid #fbfbfb;
    clip: rect(-100px 2em 9999px 0);
    /* IE9+ */
    clip: rect(-100px 3.5ch 9999px 0);
    overflow: hidden;
}
</style>
</head>
<body>
<div class="code">
.code {
    padding: 10px 10px 10px 40px;
    font-size: 13px;
    line-height: 18px;
    background-color: #eee;
    font-family: "Lucida Console", Consolas, Monaco;
    white-space: pre-wrap;
    word-break: break-all;
    position: relative;
    overflow: hidden;
}
</div>
</body>
</html>

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