checking for undefined.

[DRMRLPLS]

How do we check for undefined values in Flash 5.


My movie needs to check for values that may be passed from an outside script. 

 So I am checking to see if the value is defined or not and nothing is 

working.


I've tried :

if (value1 ==  "")

if (isNaN(value1))

if(number(value1))


What do I need to check for?  I was told that undefined values in Flash 5 are 

0, but this doesn't seem to be true.


Andrew