Stands for Hyper Text Markup Language and is the authoring language used in the creation of documents for the World Wide Web. HTML was initially created for use as a universal common document language for the World Wide Web by Tim Berners-Lee on a NeXTcube workstation using NeXTSTEP development environment. It indicates the type of information rather than the exact way it is to be presented. The actual presentation is left to the software that converts the contents to a suitable format for viewing. Text in an HTML document can be translated on-the-fly by a machine translator whereas text embedded in images and graphics (gifs, jpegs) must be localized.
HTML was set out to correct an issue which plagued web designers and the use of different web browsers, compatibility. One of the biggest differences between HTML5 and previous versions is that olders versions of HTML require proprietary apis and plugins. is that older versions of HTML require proprietary plugins and APIs. HTML5 provides one common interface to make loading elements easier.
One of the design goals for HTML5 is to support for multimedia on mobile devices. New syntactic features were introduced to support this, such as video, audio and canvas tags. HTML5 also introduces new features which can really change the way users interact with documents.
The purpose of a web browser is to read those HTML documents and compose them into visible or audible web pages for viewers. The web browser does not display the HTML tags, but uses the tags to interpret the content of the page. HTML describes the structure of a website semantically along with cues for presentation, making it a markup language rather than a programming language.