// Define the browser we have instead of multiple calls throughout the file
userAgent = navigator.userAgent.toLowerCase();
is_opera  = (userAgent.indexOf('opera') != -1);
is_saf    = ((userAgent.indexOf('applewebkit') != -1) || (navigator.vendor == 'Apple Computer, Inc.'));
is_webtv  = (userAgent.indexOf('webtv') != -1);
is_ie     = ((userAgent.indexOf('msie') != -1) && (!is_opera) && (!is_saf) && (!is_webtv));
is_ie4    = ((is_ie) && (userAgent.indexOf('msie 4.') != -1));
is_moz    = ((navigator.product == 'Gecko') && (!is_saf));
is_kon    = (userAgent.indexOf('konqueror') != -1);
is_ns     = ((userAgent.indexOf('compatible') == -1) && (userAgent.indexOf('mozilla') != -1) && (!is_opera) && (!is_webtv) && (!is_saf));
is_ns4    = ((is_ns) && (parseInt(navigator.appVersion) == 4));
is_mac    = (userAgent.indexOf('mac') != -1);