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    Display a Popup

    To follow this tutorial you'll need to have installed the SDK and learned the basics of cfx.

    This tutorial uses the action button API, which is only available from Firefox 29 onwards.

    To display a popup dialog, use the panel module. A panel's content is defined using HTML. You can run content scripts in the panel: although the script running in the panel can't directly access your main add-on code, you can exchange messages between the panel script and the add-on code.

    In this tutorial we'll create an add-on that adds an action button to the toolbar that displays a panel when clicked. The panel just contains a <textarea> element: when the user presses the return key, the contents of the <textarea> is sent to the main add-on code. The main add-on code logs the message to the console.

    The add-on consists of six files:

    • main.js: the main add-on code, that creates the button and panel
    • get-text.js: the content script that interacts with the panel content
    • text-entry.html: the panel content itself, specified as HTML
    • icon-16.png, icon-32.png, and icon-64.png: icons for the button in three different sizes

    The "main.js" looks like this:

    var data = require("sdk/self").data;
    // Construct a panel, loading its content from the "text-entry.html"
    // file in the "data" directory, and loading the "get-text.js" script
    // into it.
    var text_entry = require("sdk/panel").Panel({
      contentURL: data.url("text-entry.html"),
      contentScriptFile: data.url("get-text.js")
    // Create a button
      id: "show-panel",
      label: "Show Panel",
      icon: {
        "16": "./icon-16.png",
        "32": "./icon-32.png",
        "64": "./icon-64.png"
      onClick: handleClick
    // Show the panel when the user clicks the button.
    function handleClick(state) {;
    // When the panel is displayed it generated an event called
    // "show": we will listen for that event and when it happens,
    // send our own "show" event to the panel's script, so the
    // script can prepare the panel for display.
    text_entry.on("show", function() {
    // Listen for messages called "text-entered" coming from
    // the content script. The message payload is the text the user
    // entered.
    // In this implementation we'll just log the text to the console.
    text_entry.port.on("text-entered", function (text) {

    The content script "get-text.js" looks like this:

    // When the user hits return, send the "text-entered"
    // message to main.js.
    // The message payload is the contents of the edit box.
    var textArea = document.getElementById("edit-box");
    textArea.addEventListener('keyup', function onkeyup(event) {
      if (event.keyCode == 13) {
        // Remove the newline.
        text = textArea.value.replace(/(\r\n|\n|\r)/gm,"");
        self.port.emit("text-entered", text);
        textArea.value = '';
    }, false);
    // Listen for the "show" event being sent from the
    // main add-on code. It means that the panel's about
    // to be shown.
    // Set the focus to the text area so the user can
    // just start typing.
    self.port.on("show", function onShow() {

    Finally, the "text-entry.html" file defines the <textarea> element:

        <style type="text/css" media="all">
          textarea {
            margin: 10px;
          body {
            background-color: gray;
        <textarea rows="13" cols="33" id="edit-box"></textarea>

    Finally, save these three icon files to the "data" directory:


    Try it out: "main.js" is saved in your add-on's lib directory, and the other five files go in your add-on's data directory:


    Run the add-on, click the button, and you should see the panel. Type some text and press "return" and you should see the output in the console.

    From Firefox 30 onwards, if you use a toggle button, you can attach the panel to the button.

    Learning More

    To learn more about the panel module, see the panel API reference.

    To learn more about buttons, see the action button and toggle button API reference.


    File Size Date Attached by
    1657 bytes 2014-04-08 15:48:41 wbamberg
    3457 bytes 2014-04-08 15:48:49 wbamberg
    8635 bytes 2014-04-08 15:48:56 wbamberg
    255411 bytes 2014-04-08 20:12:52 wbamberg

    Document Tags and Contributors

    Contributors to this page: Canuckistani, wbamberg
    Last updated by: wbamberg,