HTML is the language of the Web. It is used to encode embedded directions (tags) that indicate to a Web browser how to display the contents of a document.
The HTML standard is under the authority of the World Wide Web Consortium. Unlike the HTTP standard that is used consistently across implementations, browser writers have implemented HTML differently, according to their whim, and have added their own proprietary HTML extensions (to the point that different versions of the same browser may handle the same HTML tag differently).
In your servlet code, you are advised to restrict the use of HTML to well-established tags and features. All the HTML covered here will work in all the most popular browsers, although you may ...