Event.data is proposed to be used for input events

[d.wachss@…]

In the DOM3 event specification (​http://www.w3.org/TR/DOM-Level-3-Events/#events-inputevents), beforeinput and input events have a data attribute. jQuery.event.fix sets the data attribute to whatever is passed in the on() handler.

While the data attribute is not yet implemented in any browsers, this is going to break when it happens. I have a text-input library and am trying to implement the input event correctly, but this breaks that.

Changing the jQuery data is likely impossible, but jQuery is used on more than half of all websites. Surely the jQuery foundation has some pull to change a future spec. Otherwise, using a guard like

if (event.originalEvent && handleObj.data === undefined){
  event.data = event.originalEvent.data;
}else{
  event.data = handleObj.data;

may help (with documentation that data passed in on() will overwrite the native data)

[dmethvin]

There is already at least one existing event that passes an event.data I am pretty sure. This would be a good idea though.

[dmethvin]

I've looked at this some more and think it's not the right direction.

We normalize a small subset of properties into the main event object passed to the handler. Right now the jQuery data is available consistently on event.data and the native data is always on event.originalEvent.data. This would make it more of a crapshoot as to what event.data represented which seems like a bad idea and even more confusing.

It's unfortunate that the standards group picked the same name as our existing property but there isn't much we can do about it now.

[d.wachss@…]

I understand, though this fact should be documented.

As I mentioned, the best solution is political: the proposed standard should be changed to not break jQuery, especially since it has not been implemented yet. Does the jQuery foundation have any input in the W3C? You have a greater market share (and mind share) than any individual browser.

[dmethvin]

That ship sailed long ago, the input event has been around for years but just not widely implemented. Really this is just like any other value that jQuery doesn't normalize, the best place to get it is event.originalEvent.

It's already documented:

​https://api.jquery.com/category/events/event-object/

[d.wachss@…]

Good enough.

The documentation on the Event object​https://api.jquery.com/category/events/event-object/ actually explicitly says that the data field is copied (look under "Event Properties").

When I noted this, it took me an hour of digging through the source to figure out why it wasn't working, and even

$.event.fixHooks['input'] = { props:['data'] };

wouldn't work. That fact (that the data field is set after the event is normalized) ought to be explicitly noted in Event.data​https://api.jquery.com/event.data/.

[dmethvin]

Ported to docs tracker. ​https://github.com/jquery/api.jquery.com/issues/456