gistfile1.txt

var panelLogin = require("panel").Panel({
    contentURL: "http://www.mozilla.org",
    width: 800,
    height: 500,
    contentScript: "window.addEventListener('click', function(event) {" +
                                "console.log('clicked');" +
                            "});",
    contentScriptWhen: "ready"
});

panelLogin.show();