2018 latest front-end interview questions 8

This time I bring you the latest front-end interview questions in 2018. We know that interviews are an indispensable part of front-end work. This time, the common front-end interview questions are sorted and summarized to help you get through the front-end process. The interview is a big challenge. Let’s take a look.

[Related recommendations: Front-end interview questions (2020)]

1. What is the role of doctype (document type)?

doctype enables the browser to render the page according to the rendering method specified by dtd
There are many different documents in the Web world. Only by understanding the type of document can the browser display the document correctly.
HTML also has many different versions. Only by fully understanding the exact HTML version used in the page can the browser display the HTML page completely correctly. That's what is for.
is not an HTML tag. It provides a piece of information (statement) to the browser, that is, what version of HTML is written.
If your page adds , then it is equivalent to turning on the standards mode, then the browser will You must honestly follow the standards of W3C

2. Browser standards mode (standards mode), almost standards mode (almost standards mode) and What is the difference between quirks mode?

The so-called standard mode means that the browser parses and executes the code according to W3C standards; the weird mode uses the browser's own way to parse and execute the code, because different browsers parse and execute the code differently. So we call it weird mode. Whether the browser uses standard mode or weird mode when parsing is directly related to the DTD declaration in your web page. The DTD declaration defines the type of standard document (standard mode parsing) document type, which will cause the browser to load the web page and display it in the corresponding way. , ignoring the DTD declaration will cause the web page to enter quirks mode.
Almost standards mode is set by Firefox1+, similar to the standards mode

3. What is the difference between HTML and XHTML?

HTML is a basic WEB web page design language. XHTML is a markup language based on XML. It looks somewhat similar to HTML, except for some small but important ones. The difference is that XHTML is XML that plays a role similar to HTML. Therefore, in essence, XHTML is a transition technology that combines the powerful functions of XML (somewhat) and the simple features of HTML (mostly).
The difference between HTML and XHTML is simply that XHTML can be considered as the XML version of HTML. In order to comply with XML requirements, XHTML has more strict syntax requirements.
The following are the major differences between XHTML and HTML:
XHTML requires correct nesting
All elements of XHTML must be closed
XHTML is case-sensitive
Double quotation marks XHTML uses the id attribute instead of the name attribute Problem?

Using xhtml, the page structure must contain the head

tag, and each tag structure must be closed, including empty tags. All labels must be lowercase. After using 'application/xhtml+xml', some old browsers will not support

I believe you have mastered the method after reading the case in this article. For more exciting information, please pay attention to other related articles on the php Chinese website!

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