Do Event Listeners take space in DOM?

[Dbms]

Hi,

Case: I have 5 containers inside vbox layout in a parent container. I attach listeners for tap event on each of the 5 child containers. Another way proposed is to add one event listener on the parent container, because apparently it lightens the DOM.

Questions:

1. Do Event Listeners take space in DOM?
2. If I put the event listener on the parent container only, how do I know which child container was clicked?

[mitchellsimoens]

Event listeners do not take up space in the DOM. They will take up some space in memory. If you can use just 1 listener then you will get a small performance increase over using 5 listeners.

[Dbms]

Hi Mitchell,

Thanks for the answer. Can you suggest anything for the second question also?

[olafcalderon]

jQuery('.wrapper').on('click', function(event) {
var wrap = jQuery(this);
// wrap is now the jquery object of the wrapper

var el = jQuery(event.target);
// el is now the jquery object that was clicked on

if (el.is('#mydiv')) {
// do something here if the item clicked is #mydiv
alert('this is #mydiv');
}
if (wrap.hasClass('elementclass')) {
// do something here if the wrapper of the item clicked has class of 'elementclass'
alert('this is inside .elementclass');
}
});

Here's some code as to when this would apply:

<div id='container1' class='wrapper'>
<ul>
...
</ul>
<div id='mydiv'>
...
</div>
</div>

<div id='container2' class='elementclass'>
<ul>
...
</ul>
<div id='mydiv2'>
...
</div>
</div>

if you had #mydiv inside .elementclass then two alerts would fire.


hope that helps!