Unable to clear file upload fields in web pages.

Question

When visiting any site which has the option to upload a file, I am unable to clear the field if I change my mind about uploading a file.
A website has a BROWSE or UPLOAD field and button. Pressing the button brings up the open file dialog. I select a file and select open in the dialog. If I then click on the field containing the path/file, I am presented with the open file dialog. I cannot clear or edit the field on the web page.
I originally thought it was something with the web page I visited, but then found another page did the same thing.

Answer 1

For instance if you go to this page again in Safari,
http://www.apple.com/quicktime/qtv/mwsf06/
and then select "View Source" from the View menu, then press command-f to "find" within the page and search for ".mov"
You will find this, which shows the url of the movie itself.
<param name="href" value="http://stream.qtv.apple.com/events/jan/mw2006/mmw_2006_650ref.mov">
If you copy just this part:
http://stream.qtv.apple.com/events/jan/mw2006/mmw_2006_650ref.mov
And open QuickTime Player, go to the File menu, select "Open URL" the movie will play.
If you try the same technique on the page at the link provided by your client, it will allow you to bypass the html code that may be doing an outdated compatibility check and the movie may play. Or it may tell you that you are missing components (codecs, compressors etc.) in which case, post here again.