Won't work in FireFox

programming flash
1

Does anyone know why this:


var screenWidth:Number=163;
var speed:Number=1;
var letPos:Number=32;

_root.onLoad=function(){
    ctext_mc.duplicateMovieClip('ctext2_mc',ctext_mc.getDepth()+1);
    ctext2_mc._x=ctext_mc._x-ctext_mc._width;
    chover_mc._alpha=0;
}

_root.onEnterFrame=function(){
    if(ctext_mc._x>screenWidth)
        ctext_mc._x=ctext2_mc._x-ctext_mc._width;
    if(ctext2_mc._x>screenWidth)
        ctext2_mc._x=ctext_mc._x-ctext_mc._width;
    if(ctext_mc._y>letPos){
        ctext_mc._y-=1;
        ctext2_mc._y-=1;
    } else if(ctext_mc._y<letPos) {
        ctext_mc._y+=1;
        ctext2_mc._y+=1;
    }
    if(speed==1){
        chover_mc._alpha-=(chover_mc._alpha<=0?0:10);
        ctext_mc._x+=speed;
        ctext2_mc._x+=speed;
    } else {
        chover_mc._alpha+=(chover_mc._alpha<=100?10:0);
    }
}

doesn’t work in FireFox but works in IE6 and as a standalone swf file?