buttonClip.onRelease = function(Void):Void {
    getURL(clickTag, "_blank");
}

1. Create button that covers the entire ad.
2. Create an instance of the button on the main timeline and name it "buttonClip" in the properties palette.
3. On a new layer add ActionScript to the timeline as follows:

ClickTag using ActionScript 2

actionscript, flash

ActionScript