HTML 页面开头doctype应该大写还是小写？-H5 Tutorial-php.cn

Home

Web Front-end

H5 Tutorial

HTML 页面开头doctype应该大写还是小写？

WBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWBOYWB

Jun 07, 2016 am 08:44 AM

doctypegthtmllt

这些写法都是有效的，但是哪种才是规范推荐使用的

回复内容：

HTML5 中不区分大小写！

HTML5/syntax

一个DOCTYPE必须包含以下部分，并严格按照顺序出现：

一个ASCII字符串"，大小写不敏感。

这是vs默认模板。

这是知乎的页面源码。

腾讯的。

京东的。

所以，你看着办吧。

题主你让我分心了，阿弥陀佛，工作工作。在XHTML标准下，所有标签名必须小写。这个也是个标签吧？ html 对大小写是不敏感的，不管是 doctype 还是 DOCTYPE 都是可以的，甚至 p 和 P，h1 和 H1 也都可以，哪个习惯就用哪个。 html5（包括4）不区分大小写，但是建议小写，因为xhtml是要求小写的

HTML Tip: Use Lowercase Tags
HTML tags are not case sensitive:

means the same as

.

The HTML5 standard does not require lowercase tags, but W3C recommends lowercase in HTML4, and demands lowercase for stricter document types like XHTML.

http://www.w3schools.com/html/html_elements.asp

至于doctype，我是依照建议小写的……

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Understanding H5: The Meaning and SignificanceMay 11, 2025 am 12:19 AM

H5 is HTML5, the fifth version of HTML. HTML5 improves the expressiveness and interactivity of web pages, introduces new features such as semantic tags, multimedia support, offline storage and Canvas drawing, and promotes the development of Web technology.

H5: Accessibility and Web Standards ComplianceMay 10, 2025 am 12:21 AM

Accessibility and compliance with network standards are essential to the website. 1) Accessibility ensures that all users have equal access to the website, 2) Network standards follow to improve accessibility and consistency of the website, 3) Accessibility requires the use of semantic HTML, keyboard navigation, color contrast and alternative text, 4) Following these principles is not only a moral and legal requirement, but also amplifying user base.

What is the H5 tag in HTML?May 09, 2025 am 12:11 AM

The H5 tag in HTML is a fifth-level title that is used to tag smaller titles or sub-titles. 1) The H5 tag helps refine content hierarchy and improve readability and SEO. 2) Combined with CSS, you can customize the style to enhance the visual effect. 3) Use H5 tags reasonably to avoid abuse and ensure the logical content structure.

H5 Code: A Beginner's Guide to Web StructureMay 08, 2025 am 12:15 AM

The methods of building a website in HTML5 include: 1. Use semantic tags to define the web page structure, such as, , etc.; 2. Embed multimedia content, use and tags; 3. Apply advanced functions such as form verification and local storage. Through these steps, you can create a modern web page with clear structure and rich features.

H5 Code Structure: Organizing Content for ReadabilityMay 07, 2025 am 12:06 AM

A reasonable H5 code structure allows the page to stand out among a lot of content. 1) Use semantic labels such as, etc. to organize content to make the structure clear. 2) Control the rendering effect of pages on different devices through CSS layout such as Flexbox or Grid. 3) Implement responsive design to ensure that the page adapts to different screen sizes.

H5 vs. Older HTML Versions: A ComparisonMay 06, 2025 am 12:09 AM

The main differences between HTML5 (H5) and older versions of HTML include: 1) H5 introduces semantic tags, 2) supports multimedia content, and 3) provides offline storage functions. H5 enhances the functionality and expressiveness of web pages through new tags and APIs, such as and tags, improving user experience and SEO effects, but need to pay attention to compatibility issues.

H5 vs. HTML5: Clarifying the Terminology and RelationshipMay 05, 2025 am 12:02 AM

The difference between H5 and HTML5 is: 1) HTML5 is a web page standard that defines structure and content; 2) H5 is a mobile web application based on HTML5, suitable for rapid development and marketing.

HTML5 Features: The Core of H5May 04, 2025 am 12:05 AM

The core features of HTML5 include semantic tags, multimedia support, form enhancement, offline storage and local storage. 1. Semantic tags such as, improve code readability and SEO effect. 2. Multimedia support simplifies the process of embedding media content through and tags. 3. Form Enhancement introduces new input types and verification properties, simplifying form development. 4. Offline storage and local storage improve web page performance and user experience through ApplicationCache and localStorage.

See all articles