Dan thanks It works great!! I really admire the way you code, really clean and direct, i was trying to do something like this:

var a = "Super";
var myText = a;
if (a.substring(0).match("S")) {
myText = "Yes it maches";
(doStuff to layers here)
}

Hey guys!
Is there a way to make source text drive individual animated letter layers or pre-comps?
For instance, an "A" comp or layer would be displayed when source text from a text layer has an "A". Any thoughts?
Thanks!

I don't get exactly what you are trying to do but to control the opacity with a Sine wave (or Cosine) I would do this: p=Math.sin(time) and then, since opacity is expressed as a percentile you just add this: p*100 If you want to control the amplitude and frequency of the sine wave you can try this: ...