How does HTML work? Hypertext Markup Language (HTML) is a very simple form of computer code that creates links to other places, inserts graphic images and formats text through the use of tags. Files that contain the information in the tags are stored on Web servers. When you type the URL, or address, of a Web page, you call the file from the Web server where it is stored. Your Web browser decodes the tags and turns the data into a Web page.
One of HTML's big jobs is making Web pages display correctly. When an HTML page is called, the Web server opens the file and sends its contents as one long string of ASCII text. Tags within the text, such as <P> for paragraph breaks, <BR> for soft breaks, <B> for bold text and <I> for italic text, turn that string of characters into something that's easy to read. Many Web pages use HTML tables to break the text up into various columns and sections. The <IMG SRC> (short for "image source") tag allows graphics to be displayed and gives some control over where they appear.
A browser can only display text if the tags are formatted properly. Any parts of the file the browser does not understand get left out of the translation.
HTML tags also create the links that allow you to get from one Web page to another. The tag that contains a link begins with <A HREF=> and contains the URL of the destination link. Absolute links have a full Web address beginning with http://. Relative links only have folder names, such as /myfolder/index.html. Relative links can only be used to navigate within a single Web site.
Dynamic Hypertext Markup Language (DHTML) is an extension of basic HTML that allows users to display a page based on personal actions. A good example of this is the text change function on some web pages that allows you to make the words larger or smaller.
Not all browsers offer consistent support of these additions to HTML. A page may look great in one browser, but lack information or be unreadable in another. Some browsers simply can't understand certain HTML tags, and there are slight variations in the way browsers display text and images, so designers need to be careful when they code Web pages.
HTML also allows plug-ins to play audio and video files. In order for this content to be displayed, users need to have updated versions of the plug-ins installed in their Web browsers. If you can't load all of the content on a page, you'll usually get a message from your browser directing you to the plug-in you need to install, or you'll find a link on the page to the plug-in that's needed.
Ask most people, "What is HTML?" and they'll tell you it's a language for page design. In reality, this is far from the truth.
The HTML definition changes over time as technology improves and new ways of using the Web emerge. Learn where you can find information about the latest HTML standards.