Converting onClipEvent (enterFrame) to Actionscript 3

[jgunderson]

I have an old FLA from another designer ca. 2009 or so written with Actionscript 2.0. I've been successful in converting most of it to Actionscript 3.0 to be published in HTML5 except this one function attached to a sprite which changes the transparency of the movie clip based on mouse proximity. I haven't used Flash much in recent years so any help is greatly appreciated!

onClipEvent (enterFrame)

{

    pointAtWhichAlphaReaches0 = 200;

    hyp = Math.sqrt(_xmouse * _xmouse + _ymouse * _ymouse);

    setProperty("", _alpha, 100 - hyp / pointAtWhichAlphaReaches0 * 100);

    updateAfterEvent(mouseMove);

}

[kglad]

attached to that object's timeline (which is poor coding):

var pointAtWhichAlphaReaches0:int=200;

var hyp:Number;

this.addEventListener(Event.ENTER_FRAME,f);

function f(e:Event):void{

    hyp = Math.sqrt(mouseX * mouseX + mouseY * mouseY);

this.alpha=100 - hyp / pointAtWhichAlphaReaches0 * 100;

}