What are the differences between HTML5 and HTML ?

HTML

It didn’t support audio and video without the use of flash player support.
It uses cookies to store temporary data.
Does not allow JavaScript to run in browser.
Vector graphics is possible in HTML with the help of various technologies such as VML, Silver-light, Flash, etc.
It does not allow drag and drop effects.
Not possible to draw shapes like circle, rectangle, triangle etc.
It works with all old browsers.
<HTML>, <Body>, and <Head> tags are mandatory while writing a HTML code.
Older version of HTML are less mobile-friendly.
Doctype declaration is too long and complicated.
Elements like nav, header were not present.
Character encoding is long and complicated.
It is almost impossible to get true Geolocation of user with the help of browser.
It can not handle inaccurate syntax.
Being an older version , it is not fast , flexible , and efficient as compared to HTML5.
Attributes like charset, async and ping are absent in HTML.

HTML5

It supports audio and video controls with the use of <audio> and <video> tags.
It uses SQL databases and application cache to store offline data.
Allows JavaScript to run in background. This is possible due to JS Web worker API in HTML5.
Vector graphics is additionally an integral a part of HTML5 like SVG and canvas.
It allows drag and drop effects.
HTML5 allows to draw shapes like circle, rectangle, triangle etc.
It supported by all new browser like Firefox, Mozilla, Chrome, Safari, etc.
These tags can be omitted while writing HTML code.
HTML5 language is more mobile-friendly.
Doctype declaration is quite simple and easy.
New element for web structure like nav, header, footer etc.
Character encoding is simple and easy.
One can track the Geolocation of a user easily by using JS Geolocation API.
It is capable of handling inaccurate syntax.
It is efficient, flexible and more fast in comparison to HTML.
Attributes of charset, async and ping are a part of HTML 5.

There are many HTML elements which have been modified or removed from HTML5. Some of them are listed below: