POST variables sending correctly in FF3.6 but not in FF4 beta

Question

Can anyone think of any reason why a $_POST variable might be correctly send on Firefox 3.6 but not in Firefox 4 beta. I have print_r($_POST) and this value simply doesn't show at all in FF4. Here is the input html:

<input type="image" src="images/btn_preview.gif" value="preview" name="buttonPreview"/>

Last line of the POST array in FF3.6:

[chkOrganiser] => 1 [buttonPreview_x] => 54 [buttonPreview_y] => 22 [buttonPreview] => preview )

Last line of the POST array in FF4.0:

[chkOrganiser] => 1 [buttonPreview_x] => 58 [buttonPreview_y] => 20 )  

Answer 1

see https://bugzilla.mozilla.org/show_bug.cgi?id=583211:

Firefox 4: Html input type image only submits x and y, not name when clicked.

[...]

Thanks a lot for this bug report!

However, our behavior is correct according to HTML5, which we're tracking:
<http://www.whatwg.org/html/#form-submission-algorithm&gt;, step 7, substep 3
requires just image-button.x and image-button.y to be appended to the /form
data set/, which will be submitted.

It looks like the specification follows IE and Opera in this case. If you'd
like to see this changed, please submit a bug to
, component
"HTML5 spec (editor: Ian Hickson)", or send an email to .