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Release notes for the OpenTok.js library

API reference     Tutorials

Welcome to version 2.9 of the OpenTok.js library.

If you have any questions, concerns, feedback, please let us know at our OpenTok Community.

New features
Known issues
Fixed issues
More information
How to report bugs

For details on the OpenTok.js API, see the OpenTok.js library reference.


64-bit support for the OpenTok Plugin for Internet Explorer — The OpenTok Plugin for Internet Explorer now supports in 64-bit mode). For information on testing your app with the OpenTok Plugin for Internet Explorer, see Developing with the OpenTok Plugin.

Discontinued support for Internet Explorer 9 — We have discontinued support for IE 9 in the OpenTok plugin for Internet Explorer.

New name for the OpenTok Plugin in the installer dialog box. The OpenTok Plugin is now identified as "Media plugin."

Screen-sharing extensions for Firefox — Firefox now requires that extensions, including screen-sharing extensions for OpenTok, be signed. For more infomation, see Developing a Firefox screen-sharing extension and this page on extension signing at

New Features on August 23, 2016 — OpenTok.js 2.9.0

Scalable video. The OpenTok Media Router now includes the OpenTok scalable video feature (previously in beta). For more information, see the OpenTok Media Router documentation.

Ability to use previously selected devices in the OpenTok Plugin. You can now have the OpenTok Plugin for Internet Explorer use the camera and microphone the user previously selected (from a previous visit to a page on the same HTTPS domain). For more information, see the usePreviousDeviceSelection property of the options parameter of the OT.initPublisher() method.

Features added in previous versions

Show details.


The OpenTok.js library is currently supported in:

The OpenTok.js library uses port 443. Port 443 must be open on the client network.

Known issues

The following are known issues for this version of the OpenTok on WebRTC JavaScript library.

Repositioning and resizing Publisher and Subscriber elements. Do not reparent a a Publisher or Subscriber in the HTML DOM. You can reposition these elements by changing style properties. See this information on resizing and repositioning videos.

Video streaming is prevented on networks that have firewalls that use authenticated proxies. This is due to a core issue with the current underlying WebRTC implementation. (See this Chromium bug report.)

Reconnection does not work in Firefox. The OpenTok automatic reconnection feature does not currently work in Firefox. This is due to a known issue with offline mode and peer connections in Firefox (see

One Publisher in the OpenTok Plugin for Internet Explorer. You can only add one Publisher (within all browser windows and tabs).

Cannot hide a Publisher or Subscriber in the OpenTok Plugin for Internet Explorer. Attempting to hide the a Publisher or Subscriber (by setting style.display to "none" or visibility to "hidden") causes Internet Explorer to crash.

Issue subscribing to your own stream in Internet Explorer. In Internet Explorer, you cannot subscribe to a stream published by your own client.

Sessions disconnect unexpectedly in Internet Explorer 9. We have seen this issue occur occasionally if there are other clients publishing streams in the session when the client using Internet Explorer connects. If you experience this problem, please let us know at the TokBox Plugin forum. (Please provide details, including the version of Windows, the version of Internet Explorer, the version of the Plugin, the URL of the app, and what was led up to the session disconnecting. You can get the version of the plugin by entering TBPlugin.version() in the console.)

Issue updating the OpenTok Plugin for Internet Explorer. When updating older versions of the OpenTok plug-in for Internet Explorer (prior to 2.6.0), users will be asked to install a new plug-in (instead of update). Installing the new plug-in will cause the update to take effect.

Setting the frame rate does not work in Firefox on MacOS when using the built-in FaceTime camera. Setting the frameRate option when calling OT.initPublisher() has no effect. This is the Mozilla bug report for the issue.

Setting the frame rate does not work in the OpenTok Plugin for Internet Explorer. Setting the frameRate option when calling OT.initPublisher() has no effect.

Issues setting video source for a Publisher in Firefox. In an page loaded via HTTPS, if the user clicks "Always Share" when granting access to the camera, you can only use that camera. You cannot set the video source to another camera.

The OpenTok plugin for Internet Explorer does not work in sandboxed iframes. This is an intentional limitation of the browser. The browser blocks plugin content inside a sandboxed frame.

WebRTC is a peer-to-peer protocol, and it is possible that connections will fail to connect. The most common cause for failure is a firewall that the protocol cannot traverse. When OpenTok detects this failure, the OT object dispatches an exception event object, with the code property set to 1013.

You cannot publish video on a page loaded from a file:// URL, due to browser security limitations. You need to load the page from an http:// or https:// URL. Note also, that Chrome requires you to load a page from an https:// URL (although you can use http to test a localhost URL in Chrome). For example, you can test a page from http://localhost if you have a web server set up on your local machine.

Fixed in OpenTok.js 2.9

Publisher video disappears. The Publisher video could disappear when editing text nodes on the page (for example, when using a localization library, such as localize.js). We have fixed this issue.

Audio activity indicator issues. The audio indicator was not being displayed in subscribers to and publishers of audio-only streams. Also, the audio indicator was being displayed for streams that are muted. We have fixed these issues.

The values returned by the Publisher.getImgData() and Subscriber.getImgData() methods were incorrect in the OpenTok Plugin. We have fixed this issue.

Screen-sharing was limited to 1280 by 720 pixels in the OpenTok Plugin. However, OpenTok supports screen-sharing streams up to as 1920 by 1920 pixels in size. We have fixed this issue.

OT.checkSystemRequirements() incorrectly returns 1 for old, unsupported browser versions. We have fixed this issue.

Incorrect "InvalidStateError: Peer connection is closed" error. This error was incorrectly being logged for Subscribers in new beta versions of Firefox. We have fixed this issue.

Fixed in previous versions

Show details.

More information

See the reference documentation for the OpenTok.js library.

To see sample code and to read more information on using the OpenTok.js library, see the OpenTok Tutorials and Examples page.

For documentation on the OpenTok server-side libraries, see the OpenTok server-side libraries page.

Also check out the OpenTok Help Center.

How to report bugs

We'd love to hear from you! If you have any issues or bugs, you can report them to us at