Information Browsers Ignore

Some information in an HTML document, including certain tags, is ignored when the document is viewed in a browser. These include:

There must be a space after the initial <!-- and preceding the final - ->, but you can put nearly anything inside the comment otherwise. You cannot nest comments. Microsoft Internet Explorer also supports its own proprietary way of indicating comments with <comment> </comment> tags. Comments are useful for leaving notes within a long HTML file, for example:

<!-- navigation table starts here -->