HTML and XML are two common markup languages, both of which are used to define the structure and content of documents. Although they are similar in some respects, they have many significant differences. In this article, we will discuss the differences between HTML and XML.
HTML is the markup language used to build web pages. Its purpose is to display and present content, and allows the insertion of hyperlinks, images and other elements into the content. The structure of HTML documents is very fixed, and it is strictly restricted in tag naming and attribute definition.
In contrast, XML is a more flexible markup language. It has no fixed structural limitations and can be customized to meet a variety of needs. The tags and attribute names of XML documents can be freely defined as needed to support more specific application scenarios.
HTML documents are usually parsed into a Document Object Model (DOM). DOM is a standard method for parsing HTML documents. It is commonly used by browsers to convert web pages into visual elements and supports JavaScript scripts that interact with these elements.
In contrast, the parsing method of XML documents is more flexible. XML documents can be used as a data transmission format and can be parsed into a variety of different data structures, such as tree structures, objects, hash tables, etc.
The syntax of HTML is very simple and easy to understand because it is subject to strict naming rules and semantic restrictions. In contrast, XML syntax has a certain learning curve. The tags and attributes of an XML document can be named anything you want, but this also means you need to know more to use it correctly.
The set of HTML elements is defined by the standards-setting body, and these elements have specific definitions and attributes. In contrast, XML document users are free to define their own elements and attributes, helping them better implement their needs.
One of the main uses of HTML documents is to present multimedia elements such as images, video, and audio. In contrast, XML documents do not support these elements. XML is more suitable for data transmission and data storage.
HTML documents usually appear in the file format of ".html" or ".htm" and can be opened directly in the browser. XML documents can appear in many different formats, such as XML, RSS, Atom, etc. These formats can be used for data transmission and data storage.
To sum up, although HTML and XML are both markup languages, they are very different in technical details and usage methods. HTML is used to render web content and has a fixed markup structure and limitations, while XML is more flexible to accommodate all data transfer and storage needs. In practical applications, we should choose HTML or XML according to actual needs, and choose the appropriate parsing method and data format according to needs.
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