ActionScript black color value is NaN

i'm trying to determine if a color has been supplied as an optional argument to a function. in order to determine this, i'm simply writing if(color){...} and supplying NaN if i don't want there to be a color.

however, it seems that the color black (0x000000) also equates to NaN. how can i determine if a supplied color number argument is present and black if 0x000000 is p开发者_运维百科assed as the argument?

Some source code would be appropriate.

It sounds like you are saying that the following are equivalent:

if ( NaN ) {}
if ( 0x000000 ) {}

which is true. I think you want:

if ( isFinite( color ) ) {}

Adobe help: http://help.adobe.com/en_US/AS3LCR/Flash_10.0/package.html#isFinite()