When Are CDATA Sections Essential in Script Tags?

CDATA Sections in Script Tags: When They Are Essential

CDATA sections, short for Character Data, are rarely necessary within script tags. However, their usage becomes crucial when certain conditions are met.

When an XHTML document is interpreted as XML, the JavaScript code within script tags will be parsed as parsed character data by default. This can lead to unexpected behavior, especially when the code contains characters that are significant in XML, such as "<" (less than) and "&" (ampersand).

To prevent this issue, a CDATA section can be used to enclose the JavaScript code. This ensures that the characters innerhalb the CDATA section are treated as character data, not parsed character data.

The following example demonstrates where a CDATA section is necessary:

In this example, the CDATA section prevents the JavaScript parser from interpreting the "<" and "&" characters as part of the XML document. This ensures that the code executes as intended.
On the other hand, if the JavaScript code is stored in an external source file, or if the XHTML document is not intended to be parsed as XML, a CDATA section is unnecessary. In these cases, the JavaScript code can be written without the CDATA section:

For further reading and a comprehensive guide on this topic, refer to the following resource:
https://web.archive.org/web/20140304083226/http://javascript.about.com/library/blxhtml.htm
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