CDATA tag in javascript

 

With HTML pages on the web you can just include the required Javascript between <script> and </script> tags. When you validate the HTML on your web page the Javascript content is considered to be CDATA (character data) that is therefore ignored by the validator. The same is not true if you follow the more recent XHTML standards in setting up your web page. With XHTML the code between the script tags is considered to be PCDATA (parsed character data) which is therefore processed by the validator.

Because of this, you can’t just include Javascript between the script tags on your page without ‘breaking’ your web page (at least as far as the validator is concerned).

To fix this problem we can do one of two things. The simplest way, particularly if the Javascript contains more than just one or two lines, is to make the Javascript external to the page resulting in their being nothing between the script tags to stop the page validating.

If it is just one or two lines then it is probably not worth making an external script so you will want to leave the content between the script tags and tell the validator that this is to be ignored. We do this by placing the Javascript code within a CDATA tag like this:

<script type="text/javascript">
<![CDATA[
// content of your Javascript goes here
]]>
</script>