Bug 153002 – Form submit event has a long delay before triggering when many controls on the page

• Status: NEW
• Component: Forms

[Jamie Gaskins]

A form's submit handler takes a long time to trigger when there are a lot of inputs on the page, even when they are not contained within that form.

Here is an example: http://jsbin.com/hasulikiqe/2/edit?html,js,console,output

It's a dummy todo-list app. With the JavaScript console open, you can see that it a second or so to trigger the submit handler (which just prints a message to the console) after entering text into the input field and pressing enter, even though none of the checkboxes are part of that form.

When we remove the checkboxes, the delay is gone: http://jsbin.com/rogipubexe/2/edit?html,js,console,output

[Chris Dumez]

I can reproduce with tip of tree. I see most of the CPU time spent in client code (injected bundle) under:
Running Time	Self (ms)		Symbol Name
994.0ms   24.5%	0.0	 	                                        WebKit::InjectedBundlePageFormClient::willSendSubmitEvent(WebKit::WebPage*, WebCore::HTMLFormElement*, WebKit::WebFrame*, WebKit::WebFrame*, WTF::Vector<std::__1::pair<WTF::String, WTF::String>, 0ul, WTF::CrashOnOverflow, 16ul> const&)

[Ryosuke Niwa]

Maybe we're doing the work inside Safari autofill code?

[Chris Dumez]

(In reply to comment #2)
> Maybe we're doing the work inside Safari autofill code?

Yes, I was trying to get radar-importer to create a radar for me so I could post the profile and investigation results.

[Chris Dumez]

rdar://problem/24154762