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WML <!--...--> tag

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The comment tag is used to insert a comment in the WML source code. A comment will be ignored by the browser. You can use comments to explain your code, which can help you when you edit the source code at a later moment.

This code: Produces this output:
<!--This text is a comment-->

<p>This is a regular paragraph</p>

This is a regular paragraph

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From http://www.w3schools.com (Copyright Refsnes Data)