var uagent    = navigator.userAgent.toLowerCase();
var is_safari = ( (uagent.indexOf('safari') != -1) || (navigator.vendor == "Apple Computer, Inc.") );
var is_ie     = ( (uagent.indexOf('msie') != -1) && (!is_opera) && (!is_safari) && (!is_webtv) );
var is_ie4    = ( (is_ie) && (uagent.indexOf("msie 4.") != -1) );
var is_moz    = (navigator.product == 'Gecko');
var is_ns     = ( (uagent.indexOf('compatible') == -1) && (uagent.indexOf('mozilla') != -1) && (!is_opera) && (!is_webtv) && (!is_safari) );
var is_ns4    = ( (is_ns) && (parseInt(navigator.appVersion) == 4) );
var is_opera  = (uagent.indexOf('opera') != -1);
var is_kon    = (uagent.indexOf('konqueror') != -1);
var is_webtv  = (uagent.indexOf('webtv') != -1);

var is_win    =  ( (uagent.indexOf("win") != -1) || (uagent.indexOf("16bit") !=- 1) );
var is_mac    = ( (uagent.indexOf("mac") != -1) || (navigator.vendor == "Apple Computer, Inc.") );
var ua_vers   = parseInt(navigator.appVersion);