dont want function to execute

function onButtonClicked(sender, args)
            {
                var commandName = args.get_item().get_commandName();
                if (commandName == "message")
                 {
                    onWindowLoad(<%= RadToolBar1.ClientID %>, ""); <-------what can I write here that wont throw and error on that function.. I need onWindowLoad  shouldnt execute if commandName is message...
                 }  
               
            }

            function onWindowLoad(sender, args)
            {              
                var html = "<br /><br /><br /><hr />" +
                                    "<strong>From:</strong> " + $get("from").innerHTML + "<br />" +
                                    "<strong>Sent:</strong> " + $get("sent").innerHTML + "<br />" +
                                    "<strong>Subject:</strong> " + $get("subject").innerHTML + "<br />" +
                                    $get("message-body").innerHTML;
                sender.get_contentFrame().contentWindow.setEditorContent(html);                
            }