Jquery远程验证

Question

过去一周我一直试图解决这个问题。知道这里有其他问题已经回答了类似的问题，但却无法使其发挥作用。

这是我用于远程验证的jQuery：

sponsorcode: {
            required: true,
            remote: {
                url: "../process/conn.php",
                type: "POST",
                async:false,
                data: {
                    sponsorcode: function(){
                        return $("#sponsorship").val();
                    }
                }
            }
        },

这是数据库检查（conn.php）（它还将'used'列标记为1，因为每个代码只能使用一次：

// Make sure a sponsor code was provided
if (isset($_POST['sponsorcode']) && !empty($_POST['sponsorcode'])) {

    // Escape the sponsor code to prevent SQL injection
    $code = mysqli_real_escape_string($link, $_POST['sponsorcode']);

    // Mark sponsor code as used if possible 
    $sql = 'UPDATE teachercodes SET used=1 WHERE sponsorcode="' . $code . '"';
    mysqli_query($link, $sql) or die(mysqli_error($link));

        if (mysqli_affected_rows($link)) {
            // Sponsor code hasn't been used before and is valid
            echo (json_encode(true));
        } else {
            //show that the query was successful but that the client was not found
            echo (json_encode(false));
        }
    //free the MySQL result set
    mysqli_free_result($result);
    } else {
    //the form was either not submitted or submitted with an empty value.
    echo (json_encode(false));
 }