Question

这是我的html表单。

<form id="login" action="">

            <input name="username" id="username" value="" maxlength="100" type="text" />
          <div>username:</div>

          <div id="lay_pw" style="display:none">
            <input name="password" id="password" value="" type="password" />
          <div>password:</div>
          </div>
            <input type="submit" name="go" value="login" class="main_btn1" />

        </form>

如果用户名不存在，我想检查mysql数据库中是否已存在用户名显示隐藏密码字段传输用户例如index.php。我想使用ajax检查

Answer 1

1）在根目录中创建一个新文件夹。将3个以下文件放入其中：

2）创建一个HTML文件名“ index.php ”，然后将此代码复制/粘贴并保存。

<!DOCTYPE html>
<html lang="fr_FR">
  <head>
    <meta charset="utf-8">
    <script src="//ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js"></script>
    <script src="check_username.js"></script>
    <title>Username check</title>
  </head>

  <body>
    <form id="login" action="" method="post">
       <div>username:</div>
        <input name="username" id="username" value="" maxlength="100" type="text" onkeyup="checkUsername();" />
       <div id="lay_pw" style="display:none">
        <div>password:</div>
        <input name="password" id="password" value="" type="password" />
      </div>
      <br />
      <input type="submit" name="go" value="login" class="main_btn1" />
    </form>
  </body>
</html>

3）创建一个javascript文件并将其命名为“ check_username.js ”，然后将其中的代码复制/粘贴并保存。

$.customPOST = function(data,callback){
    $.post('check_username.php',data,callback,'json');
}
//when typing, the script checks if the username exists
function checkUsername() {
  $.customPOST({username: $('#username').val()},function(r){
    //username exists
    if(r.exists == 'yes'){
     $( "#lay_pw" ).toggle(400,function(){});
    }
    else{
     $( "#lay_pw" ).css("display", "none");
    }
  });
}

4）创建一个PHP文件，将其命名为“ check_username.php ”，将此代码复制/粘贴并保存。

<?php
$link = mysql_connect('localhost','root','');
mysql_select_db('database');
$response = 'no';
if(isset($_POST['username']) && trim($_POST['username']) != ''){
 $query = mysql_query("SELECT * FROM table WHERE username = '".mysql_escape_string(trim($_POST['username']))."'", $link);
 if(mysql_num_rows($query) > 0){
  $response = 'yes';
 }
}
echo json_encode(array('exists' => $response));
?>

5）使用此示例数据库（我用它来测试这些东西）

CREATE TABLE IF NOT EXISTS `users` (
  `user` varchar(50) NOT NULL,
  `password` varchar(32) NOT NULL,
  PRIMARY KEY (`user`)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;


INSERT INTO `users` (`user`, `password`) VALUES
('test1', '5a105e8b9d40e1329780d62ea2265d8a'),
('test2', 'ad0234829205b9033196ba818f7a872b'),
('alpha', '2c1743a391305fbf367df8e4f069f9f9'),
('beta', '987bcab01b929eb2c07877b224215c92');

Answer 2

这是我的check.php文件

<?php
session_start();
include_once('inc/dbConnect.inc.php');
$message=array();
if(isset($_POST['username']) && !empty($_POST['username'])){
    $username=mysql_real_escape_string($_POST['username']);
}else{
    $message[]='Please enter username';
}

if(isset($_POST['password']) && !empty($_POST['password'])){
    $password=mysql_real_escape_string($_POST['password']);
}else{
    $message[]='Please enter password';
}

$countError=count($message);

if($countError > 0){
     for($i=0;$i<$countError;$i++){
              echo ucwords($message[$i]).'<br/><br/>';
     }
}else{
    $query="select * from user where username='$username' and password='$password'";

    $res=mysql_query($query);
    $checkUser=mysql_num_rows($res);
    if($checkUser > 0){
         $_SESSION['LOGIN_STATUS']=true;
         $_SESSION['username']=$username;
         echo 'correct';
    }else{
         echo ucwords('please enter correct user details');
    }
}
?>

如何检查MySQL表中是否已存在用户名显示隐藏密码字段

2 个答案: