sof1.js

const self = require("self");

var panelLogin = require("panel").Panel({
    contentURL: self.data.url("login.html"),
    width: 800,
    height: 500,
    contentScript: "window.addEventListener('click', function(event) {" +
                                "console.log('clicked');" +
                            "}, false);",
    contentScriptWhen: "ready"
});

panelLogin.show();