1. Changes in declaration

2. Specify the change of character encoding, it is recommended to use utf-8

3. Html5 allows

without a terminator, which is not an error

4. End tags are not allowed to be written: area, base, br, col, command, embed, hr, img, input, keygen, link, meta, param, source, track, wbr

5. Elements that can omit the end tag are: li, dt, dd, p, rt, rp, optgroup, option, colgroup, thead, tbody, tfoot, tr, td, th

6. Elements that can omit all tags are: html, head, body, colgroup, tbody

7. Previously, the attribute value text had to have double quotes, but now it can be omitted

8. See html5 markup example

9. New structural element section: container element. Chapters, headers, and footers can be used in combination with h1, h2... to indicate the document structure. Can also be used to encapsulate title content, but no title is inappropriate. When a container element needs to be directly styled or scripted to define behavior, it is recommended to use div instead of section. Function: Divide page content into chunks. Not to be confused with the article element, which has its own complete, independent content. Summary: ① Do not use the section element as a page container for setting styles, that is the job of the div element. ② If the article element, aside element, or nav element is more suitable for use, do not use the section element. ③Do not use the section element for content blocks without titles.

10. New structural element article: block-level element. Represents a piece of independent content on the page that is not contextually relevant. Emphasize independence, section emphasizes segmentation or chunking, and article emphasizes independence.

11. New structural element aside: block-level element. Represents the content position of the article element and auxiliary content related to the content of the article element.

12. New structural element Header: block-level element. The title of the entire page. There must be at least one heading (h1-h6) or hgroup element or nav element in the Header.

13. New structural element hgroup: block-level element. Used to combine titles for an entire page or a content block within a page. If there is only one main title, hgroup is not needed.

14. New structural element footer: block-level element. Footer for the content block.

15. New structural element address: inline element. Present document contact information, including: author, email, etc.

16. New structural element nav: block-level element. Navigation links. Traditional navigation, sidebar navigation, in-page navigation, and page-turning navigation. Don't use menu instead of nav in H5. The menu element is a series of menus that issue commands. It is an interactive element. More precisely, it is used in web applications.

17. New structural element figure: block-level element. An independent piece of stream content generally represents an independent unit of the document subject stream content. Use the figcaption element to add a caption to a group of figure elements.

18. New element video: defines video.

19. New element audio: defines audio.

20. New element embed: Insert various media, the format can be midi, wav, aiff, au, mp3, etc.

21

22. New element mark: highlighted or highlighted text. Quite similar to span

23. New element progress: represents the running process and displays the time-consuming function process in JavaScript.

24. New element Time: represents date and time.

Span
is used in H4. 25. New element ruby: represents ruby ??comments. Han han, which is not available in h4

26. New element rt: represents the interpretation or pronunciation of characters

27. New element rp: used in ruby ??to define the content displayed by browsers that do not support ruby ??elements.

28. New element wbr: represents soft line break. The difference with br is that br means that a line break must be performed here; while wbr means that when the width of the browser or the parent element is wide enough, no line wrapping will be performed. If the width is not enough, the line will be automatically wrapped here. Wbr is very useful for character-based languages, but it doesn't seem to have much effect on Chinese. Not available in H4.

29. New element Canvas: represents graphics. Such as: charts, images. But: the element itself has no behavior. Only a canvas is provided, and the drawing API is displayed to the client JavaScript, so that the script can draw the drawing onto this canvas.

30. New element command: represents command button. Such as: radio buttons, check boxes, buttons.

There is no

31. New element details: Indicates the detailed information that Details users require and can obtain. Can be used in conjunction with summary. Summary provides a title or legend.

33. New element keygen: indicates generating key

34. New element output: represents different types of output. Such as script

35. New element source: media element. Define media assets. Use param

36. New element menu: represents the menu list.

The use of menu in h4 is not recommended.

37. New input element type email: indicates the text input box where e-mail must be entered.

38. New input element type url: indicates that the url address must be entered

39. New input element type number: indicates that a numerical value must be entered.

40. New input element type range: indicates that numeric values ??within a certain range must be entered

41. New input element type date pickers: There are multiple new input text boxes in h5 that can select dates and times.

44.
1) Abolish elements: Elements that only some browsers support: applet, bgsound (only supported by IE), blink, marquee and other elements. bgsound (only supported by ie), marquee (only supported by ie), so they are abolished in h5. applet—can be replaced by embed or object. Bgsound—can be replaced by audio. Marquee can be replaced by js programming.
2) Tag Manual Definition: Used to combine elements. Usage Guide: Mostly used for combination of pictures and picture descriptions: