jQuery on（）方法-哪种使用方式对性能更好？

Question

Is it better to attach the on() event to the document or a closer parent?

Note : Initially this question had another aspect and a different topic. It became obsolete really quickly (typo in the source code)

Answer 1

The best key for performance using jQuery is to use an id as the initial identifier. For example:

$('#my_id').on('click', 'tag.my_class', function () {
    ...
});

This allows jQuery to go straight to the container, and then begin trawling from there.

Answer 2

if you bind the "on" event to the closest parent will produce exactly what are you looking for, click function will works fine even if it is appended to document, but in future if you append any elements with class "clickable" will also get binded. so its always good practice to append the "on" event to closest parent rather than whole document.

if you want more specific you can use

$("ul.media-grid").on('click', 'li.clickable', function () {
  alert("works")
});

as it will get the ul with the class "media-grid" and appends the event to the li's with class "clickable"