too long

Question

I want to upload 3 websql database table to server. in ajax it sends only first two table values to server and third one is null. if I change order of variables in ajax-data then also it send only first two tables and can not send last table. if i add another table then it send first three tables not last one.

please tell me whats wrong..thanks in advance..

here is javascript:

var db = application.webdb.db;
    db.transaction(function (tx) {
        tx.executeSql('SELECT * FROM a', [], function (tx, results) {
            var data = "";
            var a = [];
            for (var i = 0; i < results.rows.length; i++) {
                var row = results.rows.item(i);
                var result = {};

                for (var key in row) {
                    result[key] = row[key];
                }
                a.push(result);
            }
            tx.executeSql('SELECT * FROM b', [], function (tx, results) {
                var data = "";
                var b = [];
                for (var i = 0; i < results.rows.length; i++) {
                    var row = results.rows.item(i);
                    var result = {};

                    for (var key in row) {
                        result[key] = row[key];
                    }
                    b.push(result);
                }
                tx.executeSql('SELECT * FROM c', [], function (tx, results) {
                    var data = "";
                    var c = [];
                    for (var i = 0; i < results.rows.length; i++) {
                        var row = results.rows.item(i);
                        var result = {};

                        for (var key in row) {
                            result[key] = row[key];
                        }
                        c.push(result);
                    }

                        var url = "";
                        url = document.getElementById("url").value;
                        $.ajax({
                            type: "POST",
                            url: url,
                            async: true,
                             data: {  "a": JSON.stringify(a), "b": JSON.stringify(b) ,"c": JSON.stringify(c)},
                           // data: { "c": JSON.stringify(c), "a": JSON.stringify(a), "b": JSON.stringify(b) },
                             error: function (xhr, status, error) { alert(error); },
                            success: function (data) {
                                    alert("data:" + data);
                                var sData = JSON.parse(data);
                                //  alert("sData:"+sData);
                            }//end of sucess
                        });//end of ajax
                    });//end of c
                });//end of b
            });//end of a
    });

and php:

<?php
$a = json_decode(stripslashes($_POST['a']),true);
$b = json_decode(stripslashes($_POST['b']),true);
$c = json_decode(stripslashes($_POST['c']),true);
$arr['a'] = $a;
$arr['b'] = $b;
$arr['c'] = $c; 
print_r(json_encode($arr));
?>