Yahoo said late on Wednesday it has released a test version of its toolbar for the Mozilla Firefox Web browser. Toolbars from companies such as Yahoo enable users to go directly to particular services, such as e-mail or Web search, by simply clicking on an icon.

Amazon.com's A9 search unit also offers a toolbar for Firefox, an open source browser that is gaining in popularity as an alternative to Microsoft Corp.'s dominant Internet Explorer.

Yahoo rival Google Inc. recently hired the lead engineer of the Firefox Web browser, fueling speculation that Google will create its own version of Firefox to take on Microsoft's Internet Explorer.