为什么要使用标签?(复制)-WhyUseTheTag?[duplicate]

5  

Everything still works because the browser is plugging it in for you. You should use it because it makes your code more clear and standard.

因为浏览器正在为您插入它，所以一切仍然正常工作。您应该使用它，因为它使您的代码更加清晰和标准。

A developer looking at your code might be confused about what they're seeing at first because they would wonder where the tag is.

查看代码的开发人员可能会对他们一开始看到的内容感到困惑，因为他们可能想知道标记在哪里。

As with any standard, the tag guarantees that things will work. Currently the tag can be omitted, but I still wouldn't recommend it, to be safe. This is from the W3 spec:

与任何标准一样，标记保证一切都将正常工作。目前标签可以省略，但为了安全，我还是不推荐它。这是来自W3规范:

An html element's start tag may be omitted if the first thing inside the html element is not a comment.

如果html元素中的第一个元素不是注释，那么html元素的开始标记可能会被省略。

An html element's end tag may be omitted if the html element is not immediately followed by a comment.

如果html元素后面没有注释，则可以省略html元素的结束标记。

5  

Everything I have seen says that the HTML code needs it, but mine works fine without it.

我所看到的一切都表明HTML代码需要它，但我的代码不需要它就可以正常工作。

That's because you don't need it. The HTML specification says that you can omit the starting tags (and even the ending tags) of many elements, including html and head, which makes documents like this actually perfectly valid:

那是因为你不需要它。HTML规范说，您可以省略许多元素的起始标记(甚至是结束标记)，包括HTML和head，这使得像这样的文档实际上非常有效:

Hello world!

Browsers will create the html and head elements even if you don't write out the tags, so omit them if you want. Do note that not all browsers follow the spec properly, so while this behavior would be ideal, some browsers will parse your HTML improperly and force you to be more explicit with your structure.

浏览器会创建html和head元素，即使你不把标签写出来，如果你想的话也可以省略。请注意，并不是所有浏览器都正确地遵循规范，因此尽管这种行为是理想的，但一些浏览器会不正确地解析HTML，并迫使您在结构上更加明确。

3  

It's part of the standard. It helps tell the browser it is HTML vs XML or some other type of markup and makes it clear what kind of document it is. http://www.w3schools.com/tags/tag_html.asp

这是标准的一部分。它可以帮助告诉浏览器它是HTML vs XML或其他类型的标记，并清楚地表明它是哪种文档。http://www.w3schools.com/tags/tag_html.asp

The browser is just being nice to you and showing what is there without the tag.

浏览器对你很好，显示没有标签的东西。

0  

It is what tells various parties reading the document that it is an HTML document and that this is where it starts.

它告诉阅读文档的各方它是一个HTML文档，这是它的起点。