Javascript: Detect IE and Return Version

gistfile1.txt

/**
* Detect IE and Return Version
* @return {int} 0 if not IE, version if IE
*/
function ieVersion() {
    var rv = 0; // Return value assumes failure.
    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 );
    }
    return rv;
}