HTML
HyperText Markup Language (HTML) is a markup language used to create web pages. It was created in 1990 by Sir Tim Berners-Lee, a British computer scientist who is credited with inventing the World Wide Web. Webpages can include writing, links, pictures, and even sound and video. HTML tells web browsers what webpages should look like. HTML also adds meta information to webpages. Meta information is information about a webpage e.g., the name of the person who created the page. Web browsers usually do not show meta information.
HTML is often used with Cascading Style Sheets (CSS) and JavaScript. CSS is used to change the way HTML looks. JavaScript tells websites how to behave. It can also change HTML and CSS.
HTML is made by the World Wide Web Consortium (W3C). There are many versions of HTML. As of September 2018, the current standard of HTML is called HTML 5 and is specifically at version 5.2.
Tags
HTML uses "elements" to let the browser know how a webpage is made of. Elements are shown as "tags" in the code, written with angle brackets: <example>. Tags usually come in pairs: an opening tag defines the start of a block of content and a closing tag defines the end of that block of content. There are many kinds of tags, and each one has a different purpose. See Basic HTML Tags below for tag examples.
Some tags only work in certain browsers. For example, the <menuitem> tag, which was used to make something appear when the person presses the right button of the mouse, only worked on the Mozilla Firefox browser until version 85. Other browsers simply ignore this tag and display the writing normally. Many web page creators avoid using these "non-standard" tags because they want their pages to look the same with all browsers.
Example
Here is an example page in HTML with "Hello world!".
<!DOCTYPE html>
<html>
<head>
<title>Hi world!</title>
</head>
<body>
<p>Hello world!</p>
</body>
</html>
The Text between <html> and </html> describes the web page, and the text between <body> and </body> is the page content. <title>This is a title</title> defines the browser page title.
Example HTML tags
Here are some example HTML tags: