Change global Jquery variable value and use in PHP

Dear, I have a code that displays a dialog with a table, where after selecting the item, it is sent to an input field, via ajax. I need to use this value in a php function on the same page, so that another dialog displays a table based on the input data. I've been analyzing the use of a global jquery variable, however, I'm not getting this variable to get the input value for it to use in the future. Here is the code I use:

Javascript:

var cgc;
$(document).ready(function () {
    $(function () {
        $(".dialog").dialog({
            autoOpen: false,
            height: 400,
            modal: true,
            resizable: false,
            width: 700,                
            open: function (event, ui) { 
                $('.ui-dialog-titlebar').display("none"); 
            }
        });
        $(".opener").click(function () {
            $('input:checkbox').attr('checked', false);
            var nameD = $(this).attr("id");
            var toRemove = 'opener';
            var idDialog = "#dialog" + nameD.replace(toRemove, '');
            $(idDialog).dialog("open");
        });
        $(".botao").click(function () {
            $(".dialog").dialog("close");
        });
    });

    $(".botao").click(function () {
        getValueUsingClass(
            $(this).attr("id")
        );
    });

    function getValueUsingClass (id) {
        var chkArray = [];
        $(".chk:checked").each(function () {
            chkArray.push(
                $(this).val()
            );
        });
        var name = id;
        var toRemove = 'bt';
        var id = name.replace(toRemove, '');
        var val_id = [];

        $("input:checked").each(function () {
            val_id.push(
                $(this).attr("id")
            );
        }); 

        var selected;
        selected = chkArray.join('') + "";
        var val_id2;
        val_id2 = val_id.join('') + "";

        if (selected.length > 1) {
            if (chkArray.length > 1) {
                alert("Selecione um campo");
                $('input[id=' + id + ']').val("");
            } else {
                $('input[id=' + id + ']').val(selected);

                /* Configura a requisição AJAX */
                if(id=='Cliente') {
                    $.ajax({
                        url: 'dados_pedido.php', /* URL que será chamada */ 
                        type : 'POST', /* Tipo da requisição */ 
                        data: 'CODIGO=' + $('#Cliente').val(), /* dado que será enviado via POST */
                        dataType: 'json', /* Tipo de transmissão */
                        success: function (data) {
                            if(data.sucesso == 1) {
                                $('#codigocli').val(data.codigo);
                                $('#nomecli').val(data.nomecli);
                                $('#cnpjcli').val(data.cnpjcli);
                                $('#transpcli').val(data.transpcli);
                                $('#PagCli').val(data.PagCli);
                                cgc = data.cnpjcli;
                            }
                        }
                    });
                };
                return false; 
            }
        } else {
            alert("Nenhuma dado selecionado");
        }
    };
});

HTML and PHP:

<a href="#dialogPed3" id="openerPed3" class="opener">
    <img src="../../images/lupa.png" id="lupa3" width="16" height="16" alt = "Add"/>
</a>
<div id="dialogPed3" class="dialog">
    <?php 
        echo "teste"."<script>document.write(cgc);</script>";
    ?>
</div>

At the beginning of the jquery code there is a declared cgc variable, if I put a value immediately, type var cgc = 123, this is normally displayed in the echo of php, however when its value is changed inside the "$ (document) .ready (function () {"nothing happens, the value remains 123.

I do not know if it helps but I will explain the objective. In my page, in a certain field, there is a button that displays a dialog with a table, but this table is based on the value that is inserted in the input #cnpjcli, I have not found a way to pass this value to php the moment I call the function, what I'm trying to do is use the resource document.write (cgc); to store in a php variable and thus pass to the php function. If you have any other way to get the input value and move to the function, tb will help.