Using found address to load

Using found address to load

Sorry for this basic question.

I need  to retrieve part of a web page pointed to by a link <a class="fetch" href='web_page_address'> ...  The part I want has an id of 'unit_descr'.

When I know the address beforehand and can enter it  manually without fetching it, this works:

$(document).ready(function() {
  $('.insert_point').load('web_page_address #unit_descr');
    return false;
  });

However when I try to fetch the address and concatenate with the id of the part I want,  it will not work

$(document).ready(function() {
  var url=$('a.fetch');
  $('.insert_point').load(url + ' #unit_descr');
    return false;
  });

I suspect that $('a.fetch') selects a complete JQuery object whereas I only want  the content. .
Given that I can get hold of the content and put it into the url-variable,I am also not sure whether it is OK to  use url +' #unit_descr' to construct the argument for the load function.