cordova app with jquery, php

Question

我正在尝试使用Cordova制作一个混合应用程序，我想问两个问题？其中之一是登录，我用jquery做到了

<script type="text/javascript">
    $(document).ready(function () {
        $("#submit_btn").on("click", function(){
        var username = $("#username").val();
        var pass = $("#pass").val();
        $.ajax({
                type: "POST",
                url: "link",
                data: { username: username},
                sucess: function () {
                }
               })  
        });
    });
</script>

这是一种"正确"的方法吗？连接到数据库的最佳方式是什么？

<?php
header('Acess-Controll-Allow-Origin: *');
header('Acess-Controll-Allow-Methods: GET, POST, PATCH, PUT, DELETE, OPTIONS');
if(isset($_POST)) {
    $username = $_POST['username'];
    $pass = $_POST['pass'];
    require("connect.php");
    $sql = "INSERT INTO fields VALUES ('$username'. '$pass')";
    mysqli_query($mysqli, $sql);
}
?>

我收到此错误：注意：未定义的索引：在第 7 行的/home/wm29tzgj/public_html/areacliente/insert.php 中$username

注意：未定义的索引：在第 8 行的/home/wm29tzgj/public_html/areacliente/insert.php 中$pass

<div class="signin-form">
        <div class="container">

           <form class="form-signin" method="post" id="login-form">
            <h2 class="form-signin-heading">Log In to WebApp.</h2><hr />
            <div id="error">
            <!-- error will be shown here ! -->
            </div>
            <div class="form-group">
            <input type="email" class="form-control" placeholder="Username" name="username" id="username" />
            <span id="check-e"></span>
            </div>
            <div class="form-group">
            <input type="password" class="form-control" placeholder="Password" name="password" id="password" />
            </div>
          <hr />
            <div class="form-group">
                <button type="submit" class="btn btn-default" name="btn-login" id="btn-login">
          <span class="glyphicon glyphicon-log-in"></span> &nbsp; Sign In
       </button> 
            </div>  
          </form>
        </div>
    </div>

Answer 1

像这样：

 <script type="text/javascript">
        $(document).ready(function () {
            $("#submit_btn").on("click", function(){
            var username = $("#username").val();
            var pass = $("#password").val();
    $.ajax({
                   type: "POST",
                   url: "http://website.php",
                   data: {'username': username,"pass":pass },
                   cache: false,   
                   success: function (data) { 
                    }              
                 });
      });
    </script>

Answer 2

<script type="text/javascript">
 var username="";
 var passTxt="";
        $(document).ready(function () {
            $("#submit_btn").on("click", function(){
            username = $("#username").val();
             passTxt = $("#password").val();
    $.ajax({
                   type: "POST",
                   url: "http://website.php",
                   data: {'username': username,"pass":passTxt },
                   cache: false,   
                   success: function (data) { 
                    }              
                 });
      });
    </script>