On Fri, Nov 6, 2015 at 12:44 PM, Olli Pettay <o...@pettay.fi> wrote: > On 11/06/2015 09:28 PM, Justin Fagnani wrote: > >> You can also override addEventListener/removeEventListener on your >> element. My concern with that, and possibly an event listener change >> callback, is >> that it only works reliably for non-bubbling events. >> > How even with those? One could just add capturing event listener higher up > in the tree. >
Good point. I forgot that capturing works with non-bubbling events :( > You need to override addEventListener on EventTarget, and also relevant > onfoo EventHandler setters on Window and Document and *Element prototypes, > but unfortunately even that doesn't catch onfoo content attributes (<div > onclick="doSomething">). But one could use MutationObserver then to > observe changes to DOM. > > > -Olli > > > >> On Thu, Nov 5, 2015 at 4:16 PM, Travis Leithead < >> travis.leith...@microsoft.com <mailto:travis.leith...@microsoft.com>> >> wrote: >> >> Interesting. Alternatively, you can add .onwhatever handlers, as well >> as define your own overload of addEventListener (which will be called >> instead of the EventTarget.addEventListener method). That way you can >> capture all attempts at setting events on your element. >> >> -----Original Message----- >> From: Mitar [mailto:mmi...@gmail.com <mailto:mmi...@gmail.com>] >> Sent: Thursday, November 5, 2015 4:05 PM >> To: public-webapps <public-webapps@w3.org <mailto: >> public-webapps@w3.org>> >> Subject: Callback when an event handler has been added to a custom >> element >> >> Hi! >> >> We are using message ports to communicate with our logic and are >> wrapping the API into a custom element. The issue is that we would like to >> call >> start on a message port only after user has registered an event >> handler on the custom element instance. But it seems there is no way to get >> a >> callback when an event handler is added. >> >> So I am suggesting that there should be a callback every time an >> event listener is added to a custom element (and possibly one when removed). >> >> >> Mitar >> >> -- >> http://mitar.tnode.com/ >> https://twitter.com/mitar_m >> >> >> >
