What are the rules for using html5 tags?

Usage rules: 1. The class attribute of the tag must use lowercase letters, use "-" to separate the words, and cannot be named with built-in styles; 2. The id attribute of the tag must remain unique on the page; 3 , Tag names must use lowercase letters; 4. The use of tags must comply with the nesting rules of tags; 5. The use of tags must follow the semantics of the tags.

The operating environment of this tutorial: Windows 10 system, HTML5 version, Dell G3 computer.

What are the rules for using html5 tags

1. Naming rules

[Mandatory]class: all words must be in lowercase letters, words They are separated by - and must represent the content or function of the corresponding module or component. They must not be named after the built-in HTML style. The naming should have clear semantics.

[Mandatory]id: must remain unique in the page, and the naming should have clear semantics.

2. Tag

[Mandatory]The tag name in Html must use lowercase letters.

[Mandatory] The closing of the tag must comply with the regulations of HTML5.

[Mandatory] The use of tags must comply with the nesting rules of tags. For example: p must not be placed in p, and tbody must be placed in table.

[Recommendation] The use of tags must follow the semantics of the tags, for example:

p - Paragraph

h1,h2,h3,h4,h5,h6- Hierarchical title

strong,em - emphasize

ins - insert

del - delete

abbr - abbreviation

code - code identification

cite - The title of the work cited from the source

q - Quote

blockquote - One paragraph or long quotation

ul - Unordered list

ol - Ordered list

dl,dt,dd - Definition list

[Recommendation] Tables must not be used for layout when CSS can achieve the same requirement.

3. Attributes

[Mandatory] Attributes must use lowercase letters, and their attribute values ​​must be surrounded by double quotes.

[Suggestion] Boolean type suggestions do not add attribute values. It is recommended that custom attributes be prefixed with xxx- and data-

4 is recommended. DOCTYPE

[Mandatory] Use doctype to enable standard mode. It is recommended to use uppercase DOCTYPE

5. Language encoding

[Suggestion] It helps to improve the accessibility of the page. The correct lang attribute must be set, for example: c35479f2bccedf4d89a1cfcf7b8a4676

[Mandatory] The page must specify the character encoding meta, and it must be the first direct child element of head, for example: e0b98727b7a8c35266df47956accb156.

6. Introduction of CSS and JavaScript

[Mandatory] You must specify rel="stylesheet" when introducing css, and you must specify the type attribute when introducing css and javascript.

[Recommendation]Javascript code must be placed at the end of the page or loaded asynchronously.

7. Head content

[Mandatory] The Title tag must be set as a direct child element of the head and immediately following the charset statement.

[Mandatory] Favicon is guaranteed to be accessible, for example: eb8b05fa799a70a29c3eb6974a8ca0c3

[Mandatory] The Viewport attribute must be specified.

8. Pictures

[Mandatory] Prohibit the src value of img from being empty, and the default src attribute value must also be added to lazy-loaded pictures.

[Recommendation] Add alt attribute value to important images.

[Recommendation]Add width and height attributes to avoid page jitter.

9. Control title

[Mandatory] A control with a text title must use the label tag to associate it with its title, for example:

<label><input type="checkbox"name="confirm" value="on"> 我已确认上述条款</label>或<labelfor="user">用户：</label><inputtype="text" name="user" id="user">

10. Button

[Mandatory] The type attribute value must be specified when using the button element

11. Accessibility

[ Recommendation] When using JavaScript for form submission, native submission functionality should be enabled to work properly.

[Suggestion] Specify the type attribute of the input box according to the content type, for example: 6e290236d7c77fdce98cb15bf0dfeea2

12. Multimedia

[Recommendation] When using audio and video tags to play audio and video, you should pay attention to the format:

Audio format: MP3, WAV, Ogg

Video format: MP4, WebM, Ogg

13. Comments

[Mandatory] Detailed comments must be made on the CSS and javascript code of the page or module

Recommended tutorial: " html video tutorial》

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