html comment data-type
A syntactical production: The comment syntax indicates text within a document that is not displayed on the rendered page in the browser. A comment starts with <!-- and ends with -->.
Comments can contain other HTML elements. Comments do not nest. Start and end tags are required.
In XML mode, comments must not start or end with a dash, and must not contain two consecutive dashes.
The following is an example of an HTML Comment.
<!-- This text will not appear in the browser window. -->
Microsoft Developer Network: [Windows Internet Explorer API reference Article]