jquery select element by regex id

Why not use the attribute selector and "starts with" :

$('input[id^="edit-field-media"][id$="children-1249-checkbox"]')

You can even use both the starts with and ends with selector together ?

You can do it with ends with selector:

$(":checkbox[id$='1249-checkbox'], 
   :checkbox[id$='1259-checkbox'], 
   :checkbox[id$='1122-checkbox']");

This way you will get the checkboxes with those specific identifiers (1249,1259,1122) so in case there are similar checkboxes but with different identifiers they will not get into your selection.

So I'm assuming you want the checkboxes of those specific items among a group of similar items.

To get checkboxes with the pattern value-ANY-children-ANY-children-ANY-checkbox you can use a custom selector, like this:

$.expr[':'].mychecks = function(elem, i, match, stack) {
   reg = /value-[0-9]+-children-[0-9]+-children-[0-9]+-checkbox/g
   return reg.test(elem.id);
};

then use it like:

$(':checkbox:mychecks');
//or the equivalent
$('input[type=checkbox]:mychecks');

See working demo .