Why doesn't $.get() work with a variable containing the URL?

Why doesn't $.get() work with a variable containing the URL?

  1. function readPage(keyPage,container)
  2. {
  3.     $(function()
  4.     {
  5.         if(container=="registerCont")
  6.         {
  7.             //This works
  8.             //$.get('http://www.site.com/page.php?a=something',function(data)
  9.             //But this DOESN'T work?
  10.             $.get(keyPage,function(data)
  11.             {
  12.                 $("#"+container).html(data);
  13.             });
  14.         }
  15.     });
  16. }