how to get selector from jquery object?

Question

codes:

   var jqueryObj=$("#readme");
   alert(jqueryObj.length); // result == 0

can i get "#readme" from jqueryObj ? like:

   alert(jqueryObj.selector); //i want get "#readme"

BTW: i want to get selector,not element ID, and jqueryObj.length == 0.

Answer 1

Uhm... have you tried? http://api.jquery.com/selector/

Answer 2

Edit: Deleted 'half a page of incorrect code' due to endless discussion. Refer to decezes answer for complete solution ...