HTML Commented Script Code

Back in the "old" days, when some browsers did not understand JavaScript, the HTML comment tag was used to comment out the JavaScript code. Otherwise, the browser would print the code on the web page.

Example:

<script type="text/javascript">
<!--
alert('testing');
//-->
</script>

Later versions of browsers understand that code between script tags is not HTML, but JavaScript. If the browser's preferences tell it not to run JavaScript, the browser just ignores the code. It is smart enough to know not to print code between script tags.

Therefore, an HTML comment tag around the code was no longer needed.

Example:

<script type="text/javascript">
alert('testing');
</script>

Recently, however, we came full circle. The HTML comment tag is needed once more.

Some HTML and XHTML validators try to validate code between script tags. And the validation can fail because of that.

The solution is to do it the way it was done in the "old" days when browsers did not understand that code between script tags was JavaScript and not HTML — put the code into an HTML comment tag.

Will Bontrager