Comment

The HTML   element was used to insert a comment within an HTML document. Any content surrounded by this element will not be displayed on the webpage, but can still be seen when the source code is viewed. This element has become obsolete since HTML 2.0 and its use is not recommended. Instead, if authors wish to insert a comment, they should use.

Attributes
This element does not support any attributes.

Example:

This is a comment.

View the source code for this line of text and you will find the hidden comment.