The difference between xml and html

XML (Extensible Markup Language) and HTML (Hypertext Markup Language) are two widely used markup languages. Although they are very similar, they have significant differences. This article will introduce the differences between XML and HTML.

1. Different uses of tags

The main purpose of HTML is to define the content and structure on a web page. It uses markup to define elements such as paragraphs, titles, links, images, etc., and uses these elements to implement the layout of the page. HTML also contains CSS (Cascading Style Sheets) for rendering the styles of the page and JavaScript for scripts.

The main purpose of XML is to store and transmit data. It has no predefined elements and developers have to define their own markup according to their needs. This makes XML very flexible and can be used to store structured data such as configuration files, database records, and documents.

2. Different tagging strictness

HTML tags are grammatically loose and can tolerate certain errors or invalid tags. For example, browsers can automatically fix HTML code when closing tags or attributes are missing.

However, XML tags must fully comply with syntax rules. Any incorrect markup will cause parser errors. This ensures consistency and reliability in the transmission and processing of data between different systems.

3. Different scalability of tags

HTML's tags are predefined and developers cannot create their own tags. However, HTML provides some flexibility through CSS and JavaScript.

XML tags are extensible and new tags can be created as needed. This makes XML ideal for writing custom markup languages ​​(DSLs) and can be easily customized and extended.

4. Different data formats

HTML uses a fixed structure and syntax to express content and style. This means that the data format of HTML documents is predefined and very popular.

XML has no styles and does not contain CSS or JavaScript. Instead, its focus is on the data itself, rather than how the data is displayed. This makes XML more suitable for data exchange and storage than HTML.

5. Mark different document types

HTML has several different document types (DTD), such as HTML4, XHTML1 and HTML5. There are some syntax and elemental differences between these versions.

XML does not have an official version like HTML. Developers can create their own DTD or XML schema to define and validate markup. This also makes XML more flexible and customizable.

In short, XML and HTML are very different in terms of functionality and purpose. HTML is designed to define the content and structure of a web page, while XML is designed to store and transmit data. Although they both use markup to accomplish these tasks, their syntax and rules are different, and the context in which they are used is different. Therefore, when developing web applications or processing data, developers need to choose the right markup language based on the specific situation.

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