External Interface Issue

HI,

I am trying to call a JS function from Flash.. but unable to do so.. not sure what I am missing...

Flash Code:

--------------------------------------------

   package {

    import flash.external.ExternalInterface;
    import flash.display.MovieClip;

    import flash.events.MouseEvent;

    public class Main extends MovieClip {

               modelUsed.modelInv.addEventListener(MouseEvent.CLICK,modelUse);

          public function modelUse(event:MouseEvent):void {
            slctdTxt.text = "hello";                   /*This works*/
            ExternalInterface.call("ovrLay")             /*even tried ExternalInterface.call("ovrLay()");*/
             }

}

}

JS Code:

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<script language="JavaScript">

function ovrLay(){
    alert("asas");
}
</script>