[whatwg] HTML5 Drag-and-Drop Specification: dragenter

Daniel Cheng dcheng at chromium.org
Mon Aug 16 22:07:34 PDT 2010


You can set types of your choice in dragstart, since your drag source should
know which is which. By design, drop targets can't inspect anything but the
types until the object is actually dropped.

Daniel

On Mon, Aug 16, 2010 at 17:04, Jason Gross
<jasongross9+html5 at gmail.com<jasongross9%2Bhtml5 at gmail.com>
> wrote:

> Is it possible to get more specificity than just the type of the object
> being dragged?  For example, if I have red images and blue images, and a red
> target and a blue target, and I want to be able to drop red images only on
> the red target, and blue images only on the blue target, is there a good way
> to do this, other than globally keep track of which thing is being dragged?
> Thanks.
>
> -Jason
>
>
> On Mon, Aug 16, 2010 at 7:57 PM, Daniel Cheng <dcheng at chromium.org> wrote:
>
>> I don't think anything in the spec should prevent that. dragenter handlers
>> attached to different drop targets can check event.dataTransfer.types and
>> decide if they want to accept the drag or not.
>>
>> That being said, do any operating systems actually support multiple
>> concurrent drags and drops? WebKit has some built-in assumptions about there
>> being no more than one drag-and-drop operation (per page possibly--I can't
>> test, since I don't have access to a machine with multi-touch capabilities)
>> and I would be surprised if many other applications didn't have this
>> limitation as well.
>>
>> Daniel
>>
>> On Thu, Aug 12, 2010 at 16:26, Jason Gross <jasongross9+html5 at gmail.com<jasongross9%2Bhtml5 at gmail.com>
>> > wrote:
>>
>>> Greetings,
>>> The specification says that the dragenter event is "used to determine
>>> whether or not the drop target is to accept the drop".  Do functions bound
>>> to this event get any information about the object being dragged?  In
>>> particular, is there a good way to have N drop targets, and have each of
>>> them accept only certain draggables?  If not, it seems to me like a good
>>> feature to have, especially as multi-touch applications/devices become more
>>> prevalent.
>>> Thanks.
>>>
>>> Sincerely,
>>> Jason Gross
>>>
>>
>>
>
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