Keywords

These are words reserved for specific purposes within ActionScript syntax. As such, they cannot be used as variable, function, or label names. For example, the word on is a keyword and can only be used in a script to denote an event that triggers a script, such as on(press) , on(rollOver) , on(rollOut) , and so on. Attempting to use keywords in your scripts for anything other than their intended purpose will result in errors. (Other keywords include break, case, continue, delete, do, else, for, function, if, in, instanceOf, new, return, switch, this, typeOf, var, void, while, and with .)