Stage Blur Effect

Hi folks…
I want to make the effect, when a user rolls over a sudden movieClip, the entire stage or everything else than that movieclip, goes blurring/blur. And on roll out fades back again.
My button code look like this:

center_content.onRollOver = function() {
captionFN(true, “BILVERDY.DK VERSION 3 PÅ VEJ!!”, this);
this.onRollOut = function() { captionFN(false);

This is offcource for its captions, but the blur effect should also be under this roll over function, right?
Can anyone help me with the code?