"Why should we abandon HTML?" This question would be too long to elaborate on, so I'll try to keep it simple:
There are three main shortcomings in the development of HTML today:
1. Too simple. It cannot adapt to the needs of more and more network devices and applications. For example, mobile phones, PDAs, and information appliances cannot directly display HTML.
2. Too big. Since HTML code is not standardized and bloated, the browser needs to be smart and large enough to display HTML correctly. Obviously it's impossible to install IE6 on your PDA. There is not enough space, and the calculations cannot keep up.
3. Data and performance are mixed. In this way, if you want to change the display of your page, you must re-create the HTML. Displaying the same data on different network devices requires different HTML.
You might say that these shortcomings don't matter to you now and are not serious. But society is always progressing, technology is always developing, and people always want their work to become simpler and more efficient. The development of network equipment will not stop because of the shortcomings of HTML. Bulky desktop computers will be replaced by more and more lightweight and compact devices. Therefore, a new language is needed that can describe the data so that all devices can understand it (this creates XML); a language is needed to control the presentation so that the data can be displayed correctly on different devices (this creates XSl ).
In other words, in the future we will definitely use XML to transform data and XSL to control performance. So what now?
Now, it is obvious that thousands of original HTML pages still need to work properly and cannot be abandoned at once. Moreover, current browsers cannot directly display XML documents. Even if I can in the future, what should I do now?
So W3C formulated XHTML. XHTML is a bridge from HTML to XML. It is a transitional plan that guides people to gradually move toward standards and toward XML. Although XHTML has "X", it cannot be extended. It just strictly follows the XML specification based on HTML. It's easy to learn and requires little new knowledge.
As for XSL, CSS can now be used to implement some of the functions of XSL.
The above is the answer to "Why abandon HTML". Maybe it's not comprehensive enough, but the main point is here.