There is, here. Thanks for asking Mozilla :).

I'm on a Mac OS 10.6.4 ...and can't seem to use it, even after downloading it.... How am I supposed to get it into the text box? Drag it down? Or, should it be showing up automatically in such boxes in my FF 3.6.8 version? And, is there a version of FF 4 for the Mac?

I updated the reply with a new link to a new addon. That one should in theory work.

The latest betas of Firefox are at http://www.mozilla.com/en-US/firefox/all-beta.html . The add-on previousely suggested has not been updated since 2007.

for me it works during all 3.6.* versions until 3.6.8.

I cannot thank you enough for helping me. After downloading, I was cautioned, I have to use the "control" button on my keyboard, which turns the cursor into an X at the bottom RIGHT of the textbox, to do this, but it works perfectly. Grateful thanks!

Worked perfectly!