[whatwg] oninput event

Ian Hickson ian at hixie.ch
Mon Aug 14 17:20:03 PDT 2006

On Mon, 13 Feb 2006, Christian Schmidt wrote:
> Quote from the current working draft (10 January 2006)
> <http://whatwg.org/specs/web-forms/current-work/#the-change>:
> > UAs may delay firing the input event if the data entry is rapid.
> > Authors must not rely on this event firing once for each key press,
> > mouse input, or similar.
> I assume "key press, mouse input, or similar" refers to whenever the 
> control's value attribute changes, i.e. not key presses on arrow keys 
> etc.


> UAs may delay firing the event, but are they allowed skip it?

The spec was unclear on this. I've tried to fix it.

> If UAs are NOT allowed to skip events, what is the purpose of delaying them?
> And what exactly does delaying mean (e.g. what is the value of the control's
> value attribute when the event eventually occurs)?

The idea is that if a user types "hello" very quickly, you'll only fire an 
event at the end of the "o", rather than five times in one millisecond, 
but if he types "hell" then waits then types "o", you'll fire two events, 
one after the second "l" and one after the "o". This allows authors to 
easily implement incremental search UI.

> If UAs ARE allowed to skip events, I think it is a reasonable 
> requirement that the last event per control in a series of inputs is not 
> skipped, so that e.g. oninput="output.value=value" will always make the 
> output control be in sync shortly after the last key press (but not 
> necessarily while the user is typing rapidly).


Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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