var agt=navigator.userAgent.toLowerCase(); var is_major = parseInt(navigator.appVersion); var is_minor = parseFloat(navigator.appVersion); var is_gecko = (agt.indexOf('gecko') != -1); var is_ie = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1)); var is_ie3 = (is_ie && (is_major < 4)); var is_ie4 = (is_ie && (is_major == 4) && (agt.indexOf("msie 4")!=-1) ); var is_ie5up = (is_ie && !is_ie3 && !is_ie4); if (is_ie5up || is_gecko) { }