Lecture 2: Relevant History of HTML

Before 1997, browsers did not follow any proper HTML standard. So all sites could not be displayed properly by all browsers. In 1997, the World Wide Web Consortium (W3C) released the HTML 4 standard.  

Currently there are two groups who are involved with the HTML standardization process: W3C and WHATWG. WHATWG was created by browser companies and in recent years (since about 2007) W3C and WHATWG have started to work together. 

The present standard for HTML is known as HTML 5 (released in 2014).

The official W3C documentation regarding the HTML 5 standard can be found here: 
https://www.w3.org/TR/html5/

W3C also has a HTML validator that can check if an URL, html file or copy-pasted HTML code follows the HTML standard.
https://validator.w3.org/ 

Another very useful site is http://caniuse.com/. This site will allow you to check which HTML, CSS or JavaScript features are supported by which browsers.

Lastly, you can see the current browsers' usage shares from the link below:
http://www.w3schools.com/browsers/default.asp