getSilverlightVersion = function() {
    var knownMajorVersions = new Array(4, 3, 2, 1);
    var SLVersion;
    try {
        try {
            var control = new ActiveXObject('AgControl.AgControl');
            for (var majorVersion in knownMajorVersions) {
                var majorVersionString = majorVersion + ".0";
                if (control.IsVersionSupported(majorVersion)) {
                    SLVersion = majorVersion;
                    break;
                }
            }
            if (SLVersion == null) {
                SLVersion = 1;
            }
            control = null;
        }
        catch (e) {
            var plugin = navigator.plugins["Silverlight Plug-In"];
            if (plugin) {
                if (plugin.description === "1.0.30226.2")
                    SLVersion = 2;
                else
                    SLVersion = parseInt(plugin.description[0]);
            }
            else
                SLVersion = 0;
        }
    }
    catch (e) {
        SLVersion = 0;
    }
    return SLVersion;
}