function IsDefined(someVar) {
    var undefined;
    if (someVar != undefined && someVar != null) {
        return true;
    } else {
        return false;
    }
}

var isCleanHtmlCommandAdded = false;
function AddCleanHtmlCommand() {
    if (!isCleanHtmlCommandAdded && IsDefined(Telerik) && IsDefined(Telerik.Web) && IsDefined(Telerik.Web.UI) && IsDefined(Telerik.Web.UI.Editor)) {
        Telerik.Web.UI.Editor.CommandList["CleanHtml"] = function(commandName, editor, args)
        {
            var value = editor.get_html();
            if (value) {
                var html = $.cleanHtml(value);
                editor.set_html(html);
            }
        };
        isCleanHtmlCommandAdded = true;
    }
}