Jquery Extraparam as textbox value

Jquery Extraparam as textbox value

$().ready(function()
 {
       
       
       
       
    $("#txtpro_no").autocomplete("getplotno.php", {
        width: 260,
        matchContains: true,
        mustMatch: false,
       
       
        // This I want to pass value of textbox dynamically which is not working
        extraParams: {id: $("#txtproj_id").value},   
       
        // I Tried This Also which is not working
        //extraParams:{id: function Getval()},
       
       
        //  This Works but no dynamic value
        //extraParams: {id:1},   
       
        selectFirst: true
       
    });
   
    $("#txtpro_no").result(function(event, data, formatted){
    $("#txtplot_size").val(data[1]);
    });
});