Comments

Comments are invisible tags which can be added to the code in order to make notes or to temporarily prevent some part of the content from appearing.

A comment opens with a bracket, followed by a "bang" (exclamation mark) and two dashes, then comes the contents of the comment followed by another two dashes and a closing bracket:

Note that the opening and closing parts of the comment must be formed in this way otherwise it is just broken code. One way to remember the syntax is to think "bracket-BANG!-dash-dash, dash-dash-bracket".

Any amount of any code can be enclosed in a comment, this is called "commenting out":

Comment tags are also used to contain commands and instructions which add functions to the page.

It should be noted that while the contents of a comment are not displayed directly on the web page they are still visible to anyone who examines the source code of the page, so confidential material should not be held in comments.