HTML
The abbreviation HTML stands for “Hypertext Markup Language”. It is a text-based markup language that was developed as early as 1989 and published in its first version in 1992. Since HTML is not “programmed” but written, the designation of “programming language” is incorrect. Currently, the version HTML 4.01 is very widespread, although the successor version HTML5 is already being worked ons. More and more browsers support the newer standard. With the help of this markup language, the author of a document on the Internet can specify which information is to be displayed when it is retrieved.
Use of HTML
While HTML was initially also used to specify the appearance of the displayed page, this is now frowned upon. HTML should only be used to structure a text semantically, for example regarding headings, paragraphs, listings and numbering. However, how a web browser later outputs the information in terms of colors, fonts or font sizes is initially left up to it.
The HTML syntax
The HTML syntax follows a fixed structure. Almost every tag pair consists of a start tag and an end tag. The start tag begins with the character “<", followed by the desired element name, a list of all necessary attributes if applicable, and the closing character ">“. The closing element consists of the characters “”. For certain tags, such as listings or line breaks, the closing tag may be dispensable. Whether the tags are written in upper or lower case does not matter in HTML. It is also possible to nest tags.
Structure of an HTML document
An HTML document always consists of the same three areas. In the document type declaration, the first area, the author of the document can specify which document type definition was used. The header (HEAD) contains various meta information as well as technical information. For example, the Meta Title, JavaScript codes, CSS declarations, information about the author or the language used are recorded here. Finally, the HTML body contains the actual information that the user of a web browser has requested to be displayed by entering a URL.
Extension of HTML
Over the last two decades, numerous additional techniques have been developed that can usefully extend HTML. All design elements, which were initially used in HTML documents, are now outsourced to separate files. Here they are implemented using CSS (Cascading Style Sheets) technology, which allows the selected layout to be adapted to different end devices. Ajax allows already displayed content to be changed and reloaded without the user having to completely reload the page. JavaScript allows documents to be changed dynamically.
