Browser and incorrect HTML

Many possibilities to write incorrect HTML

- - Forget to close tags (<ul> <li> <li>)
- - Embedding incompatible tags (<p><h1></h1></p>)
- - Typos (<ui></ul>)

Browser are made to be extremely robusts to wrong HTML

- - Try to correct your HTML and give visual result
- - Try to adapt to non standard practices
- - Try to be convenient to non expert developers

- \(\Rightarrow\) Silent correction : a good looking page may have wrong HTML
- \(\Rightarrow\) Warning: Incorrect/non standard HTML may
- - - work on one browser, but not on another one
  - - work today, but not in a future version

As a Computer Scientist: Should check the validity of your HTML by external tools.