var ua = navigator.userAgent.toLowerCase();

var client = {
	isStrict:   document.compatMode == 'CSS1Compat',
	isOpera:    ua.indexOf('opera') > -1,
	isIE:       ua.indexOf('msie') > -1,
	isIE7:      ua.indexOf('msie 7') > -1,
	isSafari:   /webkit|khtml/.test(ua),
	isWindows:  ua.indexOf('windows') != -1 || ua.indexOf('win32') != -1,
	isMac:      ua.indexOf('macintosh') != -1 || ua.indexOf('mac os x') != -1,
	isLinux:    ua.indexOf('linux') != -1
};
client.isBorderBox = client.isIE && !client.isStrict;
client.isSafari3 = client.isSafari && !!(document.evaluate);
client.isGecko = ua.indexOf('gecko') != -1 && !client.isSafari;