get a value from autocomplete

Hi,
I am using the following jquery and PHP to populate an autocomplete. I will add a btnShowDetails and I woudl like to let the btnShowDetails read the value of the autocomplete (which is the company_guid? How can I do this please.

jquey for autocomplete:

$("input#txtCompanyName").autocomplete
    (
        {
            source : function (request, callback)
            {
                var data = { term : request.term };
                $.ajax
                (
                    {
                        url : "../autocomplete_company.php",
                        data : data,
                        search  : function(){$(this).addClass('working');},
                        open    : function(){$(this).removeClass('working');},
                        complete : function (xhr, result)
                        {
                            if (result !== "success") return;
                            var response = xhr.responseText;
                            var autocomplete_result = [];
                            $(response).filter ("li").each (function ()
                            { autocomplete_result.push ($(this).text ());
                        }
                    );
                    callback (autocomplete_result);
                }
            }
            );
        }
    });

Code (markup):

and it's reading from this autocomplete_company.php:

<?php
    include('includes/php_header.php');
    include($_SESSION["absolute_path"] . '/includes/connect2db.php');

    $autocomplete_term = utf8_decode($_REQUEST["term"]);
   
    $mysql_command = "CALL sp_autocomplete_company(:param_company)";
    $mysql_query = $mysql_connection->prepare($mysql_command);
    $mysql_query->bindParam(':param_company', $autocomplete_term, PDO::PARAM_STR);
    $mysql_query->execute();

    while($mysql_row = $mysql_query->fetch())
    {
        echo ("<li>" . utf8_encode($mysql_row['company_name']) . "</li>");
    }
?>

Code (markup):

and here I want to read the autocomplete value:

$('#btnShowDetails').click(function(){
    $.ajax({
        url : "get_company_details.php",
        data : 'id=HERE I WANT TO READ THE VALUE OF THE AUTOCOMPLETE',
        type : "post",
        success : function(data)
        {
            here I am displaying the result
        }
    });
});

Code (markup):