Using comments to ‘hide’ SCRIPT tag content – please stop this obsolete practice

Many years ago, when HTML3 and 4 were still widely used in the mid to late 1990s, it was a common practice to place HTML style comments, or in some cases CDATA comments inside the SCRIPT tag in an attempt to hide that content from browsers that could not process it. In those browsers the content (javascript source code) would sometimes be displayed on the page, making it quite a mess.

This practice is now obsolete, and often problematic as there are very few of those browsers in use today – primarily only for testing of legacy functionality.

Example of old approach

<script type="text/javascript">
<--
// some script
-->
</script>

NOTE: for XHTML or XML documents, the use of a CDATA style comment is still required.
<script type=”text/javascript”>
//<![CDATA[
…code…
//]]>
</script>

REFERENCES:

MSIE Conditional Comments

This approach is useful in building standards based websites and allows you to prevent it from being “polluted” by various hacks used to support MSIE. MSIE5 and newer support the use of Conditional Comments and thus allow the developer to include additional files or markup for specific versions of the browser. Other browsers will see the content as an HTML comment and thus ignore it.


<!--[if IE]><style type="text/css">@import "/css/IE=Fixes.css";</style><![endif]-->
<!--[if lt IE 5.5000]><style type="text/css">@import "/css/IE50Fixes.css";</style><![endif]-->
<!--[if IE 5.5000]><style type="text/css">@import "/css/IE55Fixes.css";</style><![endif]-->
<!--[if IE 6]><style type="text/css">@import "/css/IE60Fixes.css";</style><![endif]-->
<!--[if IE 7]><style type="text/css">@import "/css/IE70Fixes.css";</style><![endif]-->
<!--[if IE 8]><style type="text/css">@import "/css/IE80Fixes.css";</style><![endif]-->
<!--[if IE 9]><style type="text/css">@import "/css/IE90Fixes.css";</style><![endif]-->
<!--[if lt IE 7]><script type="text/javascript" src="/wiki/skins/common/IEFixes.js"></script><![endif]-->

REFERENCES: