HTML uses four characters of the ASCII character set in the marking up of its text. We have currently only used two but the complete set is as follows:
- the left angle bracket - used to denote the beginning of an HTML code sequence.
- the right angle bracket - used to denote the end of an HTML code sequence.
- the ampersand - used to signify a special character is to be produced.
- the double quote - used to reference external information, for example documents that are external to the current document.
These all have a special meaning within HTML and therefore cannot be used "as is" in HTML documents.
To use one of these characters in an HTML document, you must enter the following text instead:
- the sequence for <
- the sequence for >
- the sequence for &
- the sequence for "
Additional HTML supports certain accented characters. For example:
- the sequence for a lowercase o with an umlaut: ö
- the sequence for a lowercase n with an tilde: ñ
- the sequence for an uppercase E with a grave accent: È
Note: Unlike the rest of HTML, the above sequences are case sensitive. You cannot, for instance, use < instead of <.