Similar to other programming, markup, and markdown languages, comments in HTML provide other developers with development specific information without affecting the user interface. Unlike other languages however, HTML comments can be used to specify HTML elements for Internet Explorer only. This topic explains how to write HTML comments, and their functional applications.
<!-- Comment text -->
Anything starting with <!--
and ending with -->
is a comment. Comments cannot contain two adjacent dashes (--
), and must end with exactly two dashes (i.e. --->
is not correct).
Comments are not visible on a web page and cannot be styled with CSS. They can be used by the page's developer to make notes within the HTML, or to hide certain content during development.
For dynamic or interactive pages, hiding and showing content is done with JavaScript and CSS rather than with HTML comments.
JavaScript can be used to get the content of HTML comment nodes and these nodes can be dynamically created, added and removed from the document but this will not affect how the page is displayed.
Since HTML comments are part of the page's source code, they are downloaded to the browser along with the rest of the page. The source code can typically be viewed using the web browser's menu option to "View Source" or "View Page Source."