isWindows = isMac = false;
isMSIE = isFirefox = isSafari = false;

if (navigator.userAgent) {
	if (navigator.userAgent.indexOf('Windows')>0) 	{ isWindows = true; }
	if (navigator.userAgent.indexOf('Macintosh')>0) { isMac = true; }
	if (navigator.userAgent.indexOf('MSIE')>0) 		{ isMSIE = true; }
	if (navigator.userAgent.indexOf('Firefox')>0) 	{ isFirefox = true; }
	if (navigator.userAgent.indexOf('Safari')>0) 	{ isSafari = true; }
}