novice question: apply pre-build effect to layer

if i have a layout with 3 different layers. how do i the following: when the user clicks on a button, turn the background layer (a large color image) into grayscale with the pre-built grayscale-effect?

i looked everywhere and i cannot get the effects to "apply" when you click on the button.

can anyone help?

Example capx

For this example I keep the "state" of the effect in the global variable, and on click on the button, I check this state and execute the actions accordingly.

Works on firefox 15 and Chrome 22.

cool, thanks. i'm downloading version 104 right now to see your project, i had the 103.2 version. thanks for your help. :-)

kyatric, you're the BEST. just finished downloading 104, ran your project and the solution was so simple, and elegant. is there a FAQ list of "how do i..." topics you (or others like you have) that i can go to before posting here? the tut's section is like searching for a needle in a hay stack. any advice on finding a central-list-of "how to's" for beginners, indeterminate, etc? thanks again, i really appreciate your help.

There's a link to the FAQ thread in Kyatric's sig. Lots of good examples in there.

oops, i should have paid better attention; just went to the FAQ it is great.