function isIE() {
	if(document.all) return true;
	if(!navigator) return false;
	if(!navigator.userAgent) return false;
	if(isOpera()) return false;
	return (navigator.appName=='Microsoft Internet Explorer');
}

function isOpera() {
	if(!navigator) return false;
	if(!navigator.userAgent) return false;
	return (navigator.userAgent.indexOf('Opera')>-1);
}

function isFirefox() {
	if(!navigator) return false;
	if(!navigator.userAgent) return false;
	return (navigator.userAgent.indexOf('Firefox')>-1);
}

function isNetscape() {
	if(!navigator) return false;
	if(!navigator.userAgent) return false;
	return (navigator.userAgent.indexOf('Netscape')>-1);
}

function isMozilla() {
	if(!navigator) return false;
	if(!navigator.userAgent) return false;
	if(isNetscape() || isFirefox()) return false;
	return (navigator.appName=='Netscape');
}