HTML5 is a website development concept that enables Hypertext Markup Language (HTML) to deliver cleaner and more efficient experiences for users. A website that uses HTML5 instead of previous versions will enjoy optimized functionality and the highest website design standards currently available. HTML5 is three kinds of code: HTML, CSS, and JavaScript.
The team that created HTML5 worked out the kinks in HTML4, such as dependence on plugins and not offering an optimized experience across devices. HTML5 provides a seamless, more intuitive user experience with several new markup tags.