Open a Web Page

Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.

From Firefox 53 onwards, no new legacy add-ons will be accepted on (AMO).

From Firefox 57 onwards, WebExtensions will be the only supported extension type, and Firefox will not load other types.

Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to WebExtensions if they can. See the "Compatibility Milestones" document for more.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.

To follow this tutorial you'll need to have learned the basics of jpm.

To open a new web page, you can use the tabs module:

var tabs = require("sdk/tabs");"");

This function is asynchronous, so you don't immediately get back a tab object which you can examine. To do this, pass a callback function into open(). The callback is assigned to the onReady property, and will be passed the tab as an argument:

var tabs = require("sdk/tabs");{
  url: "",
  onReady: function onReady(tab) {

Even then, you don't get direct access to any content hosted in the tab.

To access tab content you need to attach a script to the tab using tab.attach(). This add-on loads a page, then attaches a script to the page which adds a red border to it:

var tabs = require("sdk/tabs");{
  url: "",
  onReady: runScript
function runScript(tab) {
    contentScript: " = '5px solid red';"

Learning More

To learn more about working with tabs in the SDK, see the tabs API reference.

To learn more about running scripts in tabs, see the tutorial on using tab.attach().

Document Tags and Contributors

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