[JS] Get Internet Explorer Version

get_ie_version.js

(function() {
    var head;
  
    function getInternetExplorerVersion()
    {
        var rv = -1;
        if (navigator.appName == 'Microsoft Internet Explorer')
        {
            var ua = navigator.userAgent;
            var re  = new RegExp("MSIE ([0-9]{1,}[\.0-9]{0,})");
            if (re.exec(ua) != null)
                rv = parseFloat( RegExp.$1 );
        }
        else if (navigator.appName == 'Netscape')
        {
            var ua = navigator.userAgent;
            var re  = new RegExp("Trident/.*rv:([0-9]{1,}[\.0-9]{0,})");
            if (re.exec(ua) != null)
                rv = parseFloat( RegExp.$1 );
        }
        return rv;
    }
  
    var version = getInternetExplorerVersion();
  
    if(version > 9) {
        head = document.getElementsByTagName("html")[0];
        head.className = head.className + " ie";
  
        if(version == 10) {
            head.className = head.className + " ie10";
        }
    }
})();