HTML introduction

• HTML stands for HyperText Markup Language
• HTML is a language used to build the content of webpages: browsers know how to interpret HTML so they can show this content when people visit these webpages

Why HTML?

• We want to build content that is displayed correctly in all web browsers and on every device
• The content of web pages must be easy to lay out

Standards

• To make sure every browser is able to interpret HTML and displays content in the same way, standards are required
  • The World Wide Web consortium (W3C) sets these standards and browsers are obliged to live by them
  • Not only browsers but also webdesigners must follow these standards
  • At www.w3.org you can find all standards you can use (as well as those who are in progress)

WARNING

• For every webpage you write, you should check whether your HTML code is standard compliant by using the W3C online HTML5 validator!
  • See also Tools > Validators > HTML5

Homepage filename

When you visit a website without specifying a particular webpage, for example https://www.example.com/, the web server needs to know which HTML file it should show first. This is the homepage of the website.

The filename used for the homepage depends on the type of hosting:

• On Unix/Linux hosting, the ideal name for the homepage is index.html
  • For example, when someone visits https://www.example.com/, the server will normally look for a file called index.html.
• On Windows hosting, the ideal name for the homepage is default.htm
  • For example, when someone visits https://www.example.com/, the server will automatically look for a file called default.htm.

These are conventions rather than requirements. The actual default filename is determined by the web server's configuration.

History

• The language HTML was created by Tim Berners-Lee in 1991
  • The main purpose was to enhance the collaboration between the physics who worked at CERN. They were thinking about new ways of communication and they needed a format (some form of hypertext) to link documents together by using buttons on the screen. Clicking a button simply jumped to another page with other documentation, notes, ...
  • This first version of HTML had only 18 elements defined (of which several still exist in HTML5)
• A brief history of HTML
  • HTML1 (1993)
  • HTML2 (1995)
  • HTML3 (January 1997)
    • First version published as a W3C recommendation
  • HTML4 (December 1997)
  • HTML5 (2014 - now)
    • Latest major version of HTML that has been recommended by the W3C
    • Still evolving, new features are regularly implemented