Firefox 19 for developers

Firefox 19 was released on February 19, 2013. This article lists key changes that are useful not only for web developers, but also Firefox and Gecko developers as well as add-on developers.

Changes for Web developers





Support for XForms has been removed in Firefox 19.

Changes for add-on and Mozilla developers

Note: A key change in Firefox 19 is that nsresult is now strongly typed. This will help make it easier to detect bugs that are caused by mishandling of return values, but may cause existing code to break if it's making incorrect assumptions in this regard.

  • getBrowserSelection() now returns the selected text in a text input field. As a result, gContextMenu.isTextSelected will be true when the user selects text in a text input field that is not a password field. (Firefox bug 565717)
  • Dict.jsm: Dict() now takes a JSON String. Dict.toJSON() was added, and it returns a JSON String. (Firefox bug 727967)

Interface changes


The parameter (aObserver) of addObserver() method changes from imgIDecoderObserver to imgINotificationObserver. The notify() method of imgINotificationObserver is not scriptable, so you need to use createScriptedObserver() from imgITools.


The property contentLength changed from long to int64_t.

See also

Older versions