643945 - Consider using a <button> element as the anonymous content for drop-down comboboxes instead of the <input type=button>

Status: RESOLVED FIXED

(Core :: Layout: Form Controls, defect)

Description

[(no longer active)]

This came up in bug 237842.  We should try to see if we can use a <button> element in nsComboBoxControlFrame instead of the currently used <input type=button>, which has way more overhead.

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Like so?

I left the SetAttr(type, button) call, because a <button> with no type defaults to submit, unfortunately.  This seems to be about 40ms faster on construction, and aabout 15ms faster on destruction on the testcase in bug 237842.  We could win another 40ms or so on construction by using a <div> or something, but then we'd need to do all the styling for it correctly.  Ehsan, are you willing to test this on Windows?  I think that's the one place we still show the dropmarker when using the system appearance....

Comment 2

[Boris Zbarsky [:bzbarsky]]

Even more ideally we would just not have a separate dropmarker element.  That would take more work, though.

Comment 3

[(no longer active)]

Comment on attachment 521091 [details] [diff] [review]
Like so?

This looks sane to me.  I'll test it on Windows too.

Comment 4

[(no longer active)]

This looks to be fine on Windows, too!

Comment 5

[Boris Zbarsky [:bzbarsky]]

Pushed http://hg.mozilla.org/mozilla-central/rev/256d72a8245c