$.ajax({ selector?

$.ajax({ selector?

$.ajax({ 
url: "test.php",
dataType: "html",
  success: function(data, textStatus){ 
      $("#top").empty().append(data);
...

ok now my question is a bit lame but how by this get my spec. content from test.php eg. #footer

i can load it via $('#top').load("test.php #footer");

but how to make it using this $.ajax function?