var ie=document.all?1:0;
 // test for IE 4+
var ns=document.layers?1:0;
 // test for NS 4
var dom=document.getElementById?1:0;
 // test for NS6/IE5+

var show=
ie?function(id) {
 document.all[id].style.visibility="visible";
}:
ns?function(id) {
 document.layers[id].visibility="show";
}:
function(id) {
 document.getElementById(id).style.visibility="visible";
};
var hide=
ie?function(id) {
 document.all[id].style.visibility="hidden";
}:
ns?function(id) {
 document.layers[id].visibility="hide";
}:
function(id) {
 document.getElementById(id).style.visibility="hidden"
};