HTML is the central foundation for WEB standard development_HTML/Xhtml_Web page production

HTML-centered front-end development almost means web standards. What they have in common is the idea of ​​"separation".
1. HTML is the foundation
2. CSS relies on selectors to provide visuals;
　3. Javascript relies on HTML events to drive behavior;
4. DOM provides an API to modify the HTML DOM structure for javascript calls;
5. AJAX provides XMLHTTP API to establish communication between client and server, and it is asynchronous communication;
6. XHTML is HTML reconstructed using XML. To be more structured;
7. The semantic use of HTML and micro-formats provide data extraction, which is part of SEO.