66 lines
2.2 KiB
Markdown
66 lines
2.2 KiB
Markdown
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---
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title: Comments in HTML
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localeTitle: HTML中的评论
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---
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## HTML中的评论
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comment标签是用于留下笔记的元素，主要与项目或网站相关。此标记经常用于解释代码中的某些内容或留下有关项目的一些建议。注释标记还使开发人员更容易回来并理解他在稍后阶段编写的代码。注释还可用于注释掉代码行以进行调试。
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最好在代码中添加注释，尤其是在与团队或公司合作时。
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注释以`<!--`开头，以`-->`结束，可以跨越多行。它们可以包含代码或文本，并且在用户访问页面时不会显示在网站的前端。您可以通过Inspector控制台或查看页面源来查看注释。
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### 例
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```html
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<!-- You can comment out a large number of lines like this.
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Author: xyz
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Date: xx/xx/xxxx
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Purpose: abc
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-->
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Read more: https://html.com/tags/comment-tag/#ixzz4vtZHu5uR
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<!DOCTYPE html>
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<html>
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<body>
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<h1>FreeCodeCamp web</h1>
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<!-- Leave some space between the h1 and the p in order to understand what are we talking about-->
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<p>FreeCodeCamp is an open-source project that needs your help</p>
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<!-- For readability of code use proper indentation -->
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</body>
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</html>
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```
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## 条件评论
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条件注释定义了某些编码完成时要执行的一些HTML标记。
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条件注释仅由Internet Explorer版本5到版本9 - IE5 - IE9识别。
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### 例
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```html
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<!DOCTYPE html>
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<html>
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<body>
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<!--[if IE 9]>
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<h1>FreeCodeCamp web</h1>
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<p>FreeCodeCamp is an open-source project that needs your help</p>
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<![endif]-->
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</body>
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</html>
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```
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### IE条件评论
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这些注释仅在Internet Explorer中可用，最多可用于IE9。在当今时代，你将永远不会看到它们有一个很好的变化，但了解它们的存在是很好的。条件注释是为不同客户端浏览器提供不同体验的一种方式。例如：
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```html
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<!--[if lt IE 9]> <p>Your browser is lower then IE9</p> <![endif]-->
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<!--[if IE 9]> <p>Your browser is IE9</p> <![endif]-->
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<!--[if gt IE 9]> <p>Your browser is greater then IE9</p> <![endif]-->
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```
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[关于条件评论](https://msdn.microsoft.com/en-us/library/ms537512(v=vs.85).aspx)
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