Re: alt tags no with a twist

[Note In-reply-to header above.  Current thread on WAI-IG]

Does anyone know what the various tool-tip implementations
do if instead of 

>    <IMG SRC="foo.blah" ALT="alternative_string" TITLE="tooltip_string">

they encounter

  <IMG SRC="images/blank.gif" ALT=" " TITLE="">  ?

Can one get a non-popup of the tool-tip by a null TITLE string?
Or null ALT in the absense of TITLE?

Al