Finding the id of a jquery autocomplete input from within the onItemSelect call

i have this,

$(function() {
       $('#input').autocomplete('test.php', {json: true});
     });

Code (markup):

that bring back values from the database here is my php section

$result = mysqli_query($db,$query);

while( $row = mysqli_fetch_array($result) )
{	
$aResults[] = array( "id"=>($row['s_id']) ,"value"=>($row['s_last']), "info"=>($row['s_first']) );
}
	
$return = array();

foreach ($aResults as $key => $res) {
	 $return[] =$res['value'] . ' , ' . $res['info'];
	 
}


echo json_encode($return);



		}
	}
}

Code (markup):

i would like, when i select a name from the auto suggest to be able to have the id be filled in a input text area...

uncle Google says this, but i am having a hard time implementing it.

myCallback = function(li, $input) {
    // I need to refer to the appropriate "myXxxInput" here
    alert($input.attr('id'));
}

setup = function() {
    setupInput($('#myFirstInput'));
    setupInput($('#mySecondInput'));
}

function setupInput($input) {
    $input.autocomplete('blah.php', {onItemSelect: function(li) {
        myCallback(li, $input);} });
}

Code (markup):