Why does the .selector property in jQuery not store a valid selector value?

Question

Assuming I have HTML similar to this:

<div class="fooContainer">
    <div class="barContainer">
        <a href="#">foo-bar</a>
    </div>
</div>

If in script my entry point is the anchor and I need to get to the div with the class fooContainer I can do this:

var $fooContainer = $("a").parents(".fooContainer");

This works perfectly fine as $fooContainer now holds the reference to the element in the DOM.

When I now print out the selector value like this:

console.log($fooContainer.selector)

I get the value a.parents(.fooContainer).

I was under the impression that the selector property returned a string which itself would be a valid selector value.

This is not the case though as when trying to use it as a selector like this:

$("a.parents(.fooContainer)")

It cannot find a match in jQuery 1.7.2.
And in the latest jQuery 1.8.x it even throws an exception: Error: Syntax error, unrecognized expression: a.parents(.fooContainer)

• Why does the selector property not contain a valid selector value?
• If it doesn't what would one use the selector property for?

I tried searching the jQuery documentation for information but was not able to find anything related to that property.

Answer 1

You can easily read the source code but what isn't documented in the browsable API is internal and private.

By definition.

So this is an implementation detail, and a property you really shouldn't try to use as there is no guarantee, neither for the future versions nor for any use you might imagine today.