Deprecated functionality describes a feature that is likely to be removed and should not be used in new developments.

There are various features that interpreter manufacturers add from time to time and which become standardized in a different and possibly better way, or that everyone agrees should be disregarded. Netscape's data tainting functionality is a good example of a dead end that was introduced and withdrawn soon after.

The following is a list of such deprecated functionality that should be avoided:

• Data tainting

• JavaScript extensions to HTML character entities

Warnings:

• If you use deprecated functionality, your script may fail when it is deployed on other platforms or when the platform it is hosted on is revised.