Why doesn't the .selector property in jQuery save the valid selector value?

Question

Assuming I have some HTML similar to this:

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

If in the script my entry point is an anchor and I need to go into a div with the fooContainer class, I can do this:

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

This works fine since $fooContainer now contains an element reference in the DOM.

When I now print the selector value as follows:

 console.log($fooContainer.selector) 

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

I got the impression that the selector property returned a string, which itself would be the actual value of the selector.

This is not the case when trying to use it as a selector, for example:

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

Unable to 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 this is not what, you can use the selector property for?

I tried to find jQuery documentation for information, but could not find anything related to this property.

Answer 1

You can read the source code easily, but what is not documented in the API for viewing is internal and private.

By definition.

So, this is an implementation detail and a property that you really should not try to use, because there is no guarantee, either for future versions, or for any use that you can imagine today.