var isDOM = (document.getElementById ? true : false); 
var isIE4 = ((document.all && !isDOM) ? true : false);
var isNS4 = (document.layers ? true : false);

var isNS = navigator.appName == 'Netscape';

function getRef(id) {
	if (isDOM) return document.getElementById(id);
	if (isIE4) return document.all[id];
	if (isNS4) return document.layers[id];
}

function getDivOb(divName) {
	if (isNS4) {
		return document[divName];
	} else if (isDOM) {
		return getRef(divName);
	}
}