There are some older html tags and attributes which has declared deprecated or forbidden by W3C consortium, though all modern browsers still support them but in future they may not. So it is best to know about those deprecated tags and attributes, and best practice is avoid them in your code.
Here is the list of deprecated tags:
<applet>, <basefont>, <center>, <dir>, <embed>, <font>, <isindex>, <menu>, <noembed>, <s>, <strike>, <u>
Here is the list of deprecated attributes: Continue reading “Forbidden (deprecated) HTML tags and attributes”