How do I make this animated layer code work in Firefox and IE? Thanks.

Code:
<layer name=a left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,1,1></layer>
<layer name=b left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,2,1></layer>
<layer name=c left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,3,1></layer>
<layer name=d left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,4,1></layer>
<layer name=e left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,5,1></layer>
<layer name=f left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,6,1></layer>
<layer name=g left=0 top=0 visibility=show bgcolor=#626e76 clip=0,0,7,1></layer>

<script language=javascript>
var ns=document.layers ? 1 : 0;
if (ns) {
        window.PrxOff_captureEvents(Event.MOUSEMOVE);
        var yBase = .5;
        var xBase = .1;
        var delay = 10;
        var yAmpl = 0;
        var yMax = 0;
        var step = .1;
        var ystep = 0;
        var currStep = 0;
        var tAmpl=.1;
        var Xpos = 100;
        var Ypos = 325;
        var j = 0;
        function MoveHandler(evnt) {
                Xpos = evnt.pageX;
                Ypos = evnt.pageY;
        }
        window.onMouseMove = MoveHandler;
        function animateLogo() {
                yBase = window.innerHeight/2;
                xBase = window.innerWidth/2;
                for (j=0; j<7 ;j++) {
                        document.layers[j].top = Ypos + Math.cos((Math.sin(currStep/10)))*yBase*(Math.cos(currStep/10))*Math.sin((currStep/1 + j*50));
<!--                        document.layers[j].left =Xpos + Math.sin((20*Math.sin(currStep/20)))*xBase*(Math.cos(currStep/10))*Math.sin((currStep)/10);-->
                }
        currStep += step;
        setTimeout("animateLogo()", delay);
        }
animateLogo();
}
</script>