Hjælp til at virke i Moz.

Har denne stump kode, men kan ikke finde ud af, at få det til at virke i Moz. =/
Nogen der kan hjælpe?

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

<script language="javascript" type="text/javascript">
var ns, ns6, ie, newlayer;

ns4 = (document.layers) ? true : false;
ie4 = (document.all)? true:false
ie5 = (document.getElementById)? true:false
ns6 = (document.getElementById && !document.all)?true:false;

function getLayerStyle( lyr ){
if( ns4 ){
return document.layers[lyr];
} else if( ie4 ){
return document.all[lyr].style;
} else if( ie5 ){
return document.all[lyr].style;
} else if( ns6 ){
return document.getElementById(lyr).style;
}
}

function ShowHide(layer){
newlayer = getLayerStyle(layer)

var styleObj = (ns4)? document.layers[layer] : (ie4)? document.all[layer].style : document.getElementById(layer).style;

if (newlayer.visibility == "hidden") {
newlayer.visibility = "visible";
styleObj.display = ""
}
else if (newlayer.visibility == "visible") {
newlayer.visibility = "hidden";
styleObj.display = "none"
}
}
</script>