fadeIn -- what?

[instantjesus]

Hi! I'm trying to analyze the sample file load_images.fla which is delivered with flash mx... and here's my problem:
there's a line in the first frame in the actions layer which is as follows:

if (whichPic<5 && !fadeIn && !fadeOut) {.........}

now what is "fadeIn" or "fadeOut"? I thought it might be a method of the MovieClip-Object, but it's not listed in the actionscript-reference. then I thought, it could be a method defined within the flash-movie itself, but it isn't (at least i couldn't find it). so what is it?

thanx for your hints on that problem!

[upuaut]

They are boolean variables. It's saying basically

if whichPic is less than 5 and fadeIn is false and fadeOut is false do this~~>{.........}