Question

If I write :

<div class="wrapper">
 <div>
    <input  type="text" class="xxx"/>
 </div>
 <div>
    <input  type="text" class="yyy"/>
 </div>
</div>

question :

when I write: $(".wrapper").on("click",".yyy",function () {}); :

Does it also listen ( and ignores) the .xxx events ?

or is it just listen to the .wrapper and filters all non ".yyy" elements events?

Answer 1

It binds the click event to .wrapper and if the target was .yyy, it will execute the function. This allows you to remove/replace .yyy at any time, via ajax or whatever, and keep the bound event.