What is the difference between html5 and 4?

Differences: 1. HTML5 simplifies the syntax. For example, the file type declaration only needs to be written as ""; 2. HTML5 document parsing is no longer based on SGML; 3. HTML5 new Semantic tags have been added, some tags related to web page beautification have been abolished, and the separation of style and structure has been made more complete, etc.

The operating environment of this tutorial: Windows 7 system, HTML5 version, Dell G3 computer.

HTML5 has developed at an alarming rate since its official launch in 2010. Now mainstream browsers basically support HTML5 (except for some individual features that have browser compatibility issues). This shows that HTML5 is becoming more and more popular. welcome. It can be predicted that HTML5 will become the mainstream technology of web front-end in the near future. HTML5 special effects are better adapted to the mobile Internet era and can better support multimedia running on mobile devices.

What are the differences between HTML5 and HTML4?

1. Syntax simplification

The introduction of html5 has simplified the syntax. For example, for the doctype in the head, we only need to write&lt ;!doctype html> will do.

And html4 needs to be written as:

#2. In terms of standards

HTML5 document parsing is no longer based on SGML (Standard Generalized Markup Language) standard, but formed its own set of standards.

3. In terms of tags,

added new semantic tags, including

,

,

,

,

,

,

,

Abolish some web page beautification tags to make the separation of style and structure more complete, including

, , , ,

, ,

By adding

In the past, when playing multimedia on a web page, you needed to use ActiveX or Plug-in. With HTML5, you can use the

4. In terms of attributes

Added some form attributes, mainly the enhancement of the input attribute

<!-- 此类型要求输入格式正确的email地址 -->
<input type=email >
<!-- 要求输入格式正确的URL地址  -->
<input type=url >
<!-- 要求输入格式数字，默认会有上下两个按钮 -->
<input type=number >
<!-- 时间系列，但目前只有 Opera和Chrome支持 -->
<input type=date >
<input type=time >
<input type=datetime >
<input type=datetime-local >
<input type=month >
<input type=week >
<!-- 默认占位文字 -->
<input type=text placeholder="your message" >
<!-- 默认聚焦属性 -->
<input type=text autofacus="true" >
其他标签新增了一些属性,
<!-- meta标签增加charset属性 -->
<meta charset="utf-8">
<!-- script标签增加async属性 -->
<script async></script>
使部分属性名默认具有boolean属性
<!-- 只写属性名默认为true -->
<input type="checkbox"  checked/>
<!-- 属性名="属性名"也为true -->
<input type="checkbox"  checked="checked"/>

5. In terms of storage

New WebStorage, including localStorage and sessionStorage

Introduced IndexedDB and Web SQL, allowing to create database tables and store data on the browser side. The difference between the two is that IndexedDB is more like It is a NoSQL database, while WebSQL is more like a relational database. W3C no longer supports WebSQL.

Introduced the application cache (application cache), which can cache the web and use it when there is no network. By creating a cache manifest file and creating an application cache, it provides PWA (Progressive Web App) Underlying technical support.

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