// browser_ver.js

var agt = navigator.userAgent.toLowerCase();
var app = navigator.appName.toLowerCase();
var is_major = parseInt(navigator.appVersion);	// browser version

var is_nav  = (app == "netscape");
var ns4 = (is_nav && (is_major >= 4));	// 4 or higher
var ns5 = (is_nav && (is_major >= 5));	// 5 or higher

var is_ie = (agt.indexOf("msie") != -1);
var ie4 = (is_ie && (is_major >= 4));	// 4 or 5
var ie5 = (is_ie && (is_major >= 4) && (agt.indexOf("msie 5.")!=-1) );		// ie 5

var is_mac = (agt.indexOf("mac") != -1)