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POSending data with an event listener
 

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    <p>I have a predicament: I want to send some data with an event listener but also be able to remove the listener. Here's the standard closure approach...</p> <pre><code>var fn = function(e){method(e,data)}; el.addEventListener('click',fn,false); el.removeEventListener('click',fn,false); </code></pre> <p>and you could remove the event, just fine. But say, the element was removed from the DOM? Then, you'd be left with the <code>fn</code> function sitting around. After removing a couple thousand DOM elements, it will result in something of a memory leak.</p> <p>I've considered attaching a DOMNodeRemoved event handler, that would remove any left over functions/data along with the removed node. But apparently, that event isn't cross-browser compatible.</p> <p>The only other option I've come up with would be modifying the element's DOM. Consider...</p> <pre><code>el.MyEventData = function(e){method(e,data)}; el.addEventListener('click',el.MyEventData,false); el.removeEventListener('click',el.MyEventData,false); </code></pre> <p>Is modifying the DOM acceptable in this situation? The only sticky part of that solution is when you try to add more than one event listener. Let's say we made a custom function to parse the adding/removing of events...</p> <pre><code>function makeEvent(fn,data){ var dataFn = function(e){fn(e,data)}; //create object to hold all added events el.myEvents = {}; //make ID for this specific event var eventID = ranString(); //add the event to the events object el.myEvents[eventID] = [fn,dataFn]; //finally add the listener el.addEventListener('click',dataFn,false); } function destroyEvent(fn){ //find all fn references for(var id in el.myEvents){ if (el.myEvents[id][0] == fn){ el.removeEventListener('click',el.myEvents[id][1],false); el.myEvents[id] = null; } } } </code></pre> <p>It still modifies the DOM, as before, and certainly isn't a very elegant solution either. Does anyone know of any alternative, better method for passing data?</p> <p><em>EDIT</em>: So, I've looked into a little of jQuery's data/event scripts. I don't completely understand the code, so if someone would clarify, it would be helpful. But it seems as though they use a similar method, by making some type of el.cache property, that holds event data.</p>
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    1. COthe jquery event is based on the idea of [dean edward](http://dean.edwards.name/weblog/2005/10/add-event/), is probably the best solution to you
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    2. COI've looked his script up, but it has no further way of implementing data sending than the examples I've already listed.
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