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Firefox fails to load properly a page which calls javascripts. Error console displays error: Permission denied to get property Window.API


The problem, occurs with pages in a website which include simple Spanish language exercises. The pages in question call javascripts to allow users to complete the exercises interactively.

I am the author of the pages and when I open these pages as stored in my hard drive, Firefox (Vers 3.0.16) opens the pages OK.

However, when I request one of these page from the website server, Firefox (same version) displays the page as if it could not 'see' the script.

When I look at the Error Console, I see that it displays the error message: Permission denied to get property Window.API (the error message appears to refer to the corresponding javascrip (.js file)

Internet Explorer 7 opens the same pages without any problem.

Additional System Details

Sites Affected


Installed Plug-ins

  • getplusplusadobe16291
  • Adobe PDF Plug-In For Firefox and Netscape "9.4.1"
  • The QuickTime Plugin allows you to view a wide variety of multimedia content in Web pages. For more information, visit the QuickTime Web site.
  • NPRuntime Script Plug-in Library for Java(TM) Deploy
  • RealJukebox Netscape Plugin
  • RealPlayer(tm) LiveConnect-Enabled Plug-In
  • Default Plug-in
  • Shockwave Flash 10.1 r102
  • Adobe Shockwave for Director Netscape plug-in, version
  • iTunes Detector Plug-in
  • Picasa plugin
  • Next Generation Java Plug-in 1.6.0_22 for Mozilla browsers
  • Windows Presentation Foundation (WPF) plug-in for Mozilla browsers
  • RealPlayer(tm) HTML5VideoShim Plug-In
  • Google Update
  • Wacom Dynamic Link Library


  • User Agent: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-GB; rv: Gecko/2009120208 Firefox/3.0.16 (.NET CLR 3.5.30729)

More Information

  • Top 10 Contributor
  • Moderator
10752 solutions 96760 answers

No problems here with that page with Firefox 3.6.13 on Linux.

Reload the web page and bypass the cache with:

  • Press and hold Shift and left-click the Reload button.
  • Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
  • Press "Cmd + Shift + R" (MAC)

See Keyboard shortcuts - Perform common Firefox tasks quickly and Use mouse shortcuts to perform common tasks in Firefox

Start Firefox in Troubleshoot Firefox issues using Safe Mode to check if one of the add-ons is causing the problem (switch to the DEFAULT theme: Tools > Add-ons > Themes).

  • Don't make any changes on the Safe mode start window.