You should realize that jQuery works with the HTML DOM tree in the client side. jQuery doesn’t work directly on JSF components as you’ve written in the JSF source code, but jQuery works directly with the HTML DOM tree which is generated by those JSF components. You need to open the page in webbrowser and rightclick and then View Source. You’ll see that JSF prepends the ID of the generated HTML input elements with the IDs of all parent NamingContainer components (such as <h:form>, <h:dataTable>, etc) with : as default separator character. So for example
<h:form id="foo">
<p:selectManyCheckbox id="bar" />
...
will end up in generated HTML as
<form id="foo" name="foo">
<input type="checkbox" id="foo:bar" name="foo:bar" />
...
You need to select elements by exactly that ID instead. The : is however a special character in CSS identifiers representing a pseudo selector. To select an element with a : in the ID using CSS selectors in jQuery, you need to either escape it by backslash or to use the [id=...] attribute selector or just use the old getElementById():
var $element1 = $("#foo\\:bar");
// or
var $element2 = $("[id='foo:bar']");
// or
var $element3 = $(document.getElementById("foo:bar"));
If you see an autogenerated j_idXXX part in the ID where XXX represents an incremental number, then you must give the particular component a fixed ID, because the incremental number is dynamic and is subject to changes depending on component’s physical position in the tree.
As an alternative, you can also just use a class name:
<x:someInputComponent styleClass="someClassName" />
which ends up in HTML as
<input type="..." class="someClassName" />
so that you can get it as
var $elements = $(".someClassName");
This allows for better abstraction and reusability. Surely those kind of elements are not unique. Only the main layout elements like header, menu, content and footer are really unique, but they are in turn usually not in a NamingContainer already.
As again another alternative, you could just pass the HTML DOM element itself into the function:
<x:someComponent onclick="someFunction(this)" />
function someFunction(element) {
var $element = $(element);
// ...
}