//  Browser check	if (navigator.appName.indexOf('Microsoft') >= 0 && navigator.appVersion.indexOf('3.') >=0) {		okbrowser = false;		}	else {		okbrowser = true;		}	//  Load images	imag = new Array();			imag[0]="images/nav_firm_on.gif";			imag[1]="images/nav_lawyers_on.gif";			imag[2]="images/nav_practice_on.gif";			imag[3]="images/nav_contact_on.gif";		im = new Array()	if(document.images) {		for (var i = 0; i < imag.length; i++) {			im[i] = new Image();			im[i].src = imag[i];			}		}	//  Mouseover functions	function on(s) {	if (okbrowser) {		document.images[s].src= "images/" + s + "_on.gif";		}	}	function off(s) {	if (okbrowser) {		document.images[s].src= "images/" + s + "_off.gif";		}	}