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ECMAScript binding for EventListener

From: David Flanagan <david@oreilly.com>
Date: Thu, 14 Jun 2001 14:01:40 -0700
Message-Id: <200106142101.OAA04572@oxymoron.oreilly.com>
To: www-dom@w3.org

In the Level 2 DOM, the ECMAScript binding for the EventListener
interface is simply a function reference.

While this is very convenient for JavaScript programmers, it sacrifices
the power that comes with treating EventListener as a true object.
Specifically, the current binding allows us to register only functions
as event handlers, and does not allow us to register object methods as
handlers.  (Mozilla currently invokes any event handler function you
register as a method of the event target.)

I'd like to propose that the next edition of the specification broaden
the ECMAScript binding so that EventListener may be either a function or
an object.  If an object o is registered, it must have a property named
handleEvent that contains a function reference.  When the appropriate
event occurs, this function is invoked _as a method of the object o_.

As a trivial example, I ought to be able to write code like this:

	element.addEventListener("click",
		   { 
		      message: "Hello world",
		      handleEvent: function(e) { alert(this.message); }
                   },
		   false);

Anyone have thoughts about this?

     David Flanagan
Received on Thursday, 14 June 2001 17:58:20 GMT

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