The HyperText Markup Language (HTML) (literal translation: to hypertext markup language), in computer science is the markup language usually used for formatting and layout of hypertext documents available on the World Wide Web in the form of web pages.
It is a language in the public domain, whose syntax is defined by the World Wide Web Consortium (W3C), which is derived from another language having more general purposes, the SGML.
General features
HTML is a markup language that describes how to layout or graphical display (layout) content, textual and otherwise, of a webpage through formatting tags. Though HTML supports the inclusion of scripts and external objects such as images or movies, is not a programming language: failing to provide any definition of variables, data structures, functions and control structures that can implement programs, its code is in only able to structure and decorate textual data.
HTML, XHTML or its variant, aims to manage the content associating or specifying both the graphic structure (layout) within the web page to be realized by using different tags. Each tag (eg <h1> or <p>) specifies a different role of the content that it marks (then the <h1> will define greater importance of the <p> tag). The formatting in the text consists of the insertion of markers or labels, said tags, which describe features such as the function, the color, the size, the relative position within the page. The browsers that read the code shows the user default formats for each tag that meet (so for example the contents marked with the <h1> will 18pt font and contents marked by <p> will 12pt font). However, this format is completely under your control, you can change it in the settings of your browser.
When a hypertext document written in HTML is stored in a file its extension is typically .html or .htm.
