Question

我有一个简单的html表单，它接受用户名和密码并将其注册到数据库中。但是，即使在提交表单之前，只要页面加载，它就会执行以下php if语句。以下是那段代码。

if (($_POST['reg_username']=="") || ($_POST['reg_password']==""))
{ ?>
<script> alert("please enter both email and password"); </script>

<? }

完整的PHP代码如下。这不是最终的代码所以我仍然没有加密密码和一切，但我只是测试它。先谢谢你们。

if (($_POST['reg_username']=="") || ($_POST['reg_password']==""))
{ ?>
<script> alert("please enter both email and password"); </script>

<? }


$reg_username=mysql_real_escape_string($_POST['reg_username']);
$reg_username=htmlspecialchars($reg_username);
$reg_password=mysql_real_escape_string($_POST['reg_password']);
$reg_password=htmlspecialchars($reg_password);



if(!empty($reg_username) && !empty($reg_password))
{

if (isset($reg_username) && isset($reg_password))
{
mysql_select_db($db, $dbconnect);
mysql_query("INSERT into students(username,password) VALUES    
('$reg_username','$reg_password')");
}
}

?>

Answer 1

为什么必须在PHP中包含这些标记？为什么你不单独做。这是Javascript（jQuery）的一个例子：

请注意，自从我在一分钟内编写该代码段后，可能会出现一些拼写错误和语法错误。

<script type="text/javascript">

$(document).ready(function() {

("#login_form").submit(function() {

var username = ("#selector").val();
var password = ("#password").val();

if(username == "" && password == "") {

alert("please enter both email and password");

}
}

)};
</script>

Answer 2

改变这个：

if (($_POST['reg_username']=="") || ($_POST['reg_password']==""))
{ ?>
<script> alert("please enter both email and password"); </script>

<? }

进入这个：

if(isset($_POST['reg_username']) || isset($_POST['reg_password'])) 
{
if (($_POST['reg_username']=="") || ($_POST['reg_password']==""))
{ ?>
<script> alert("please enter both email and password"); </script>

<?php }
}

Answer 3

 if(isset($_POST['SubmitButtonName'])){ //check if form was submitted
      unset($_POST['SubmitButtonName']);
      if (($_POST['reg_username']=="") || ($_POST['reg_password']==""))
      { ?>
           <script> alert("please enter both email and password"); </script>
      <? }
 }

请记住更改SubmitButtonName

Answer 4

      <script>
     $(document).ready(function(){
     $("#submit").click(function(){
    var register_name=$('#reg_username').val();
var register_password=$('#reg_password').val();

if(register_name =="")
{
alert("please enter your name");
return false;
} else if(register_password =="")
{
alert("please enter your password");
return false;
}
else
{
return true;
}
        });
       });
           </script>
        </head>
        <body>
          <form action="" method="post">
          Register name:<input type="text" name="reg_username" id="reg_username"><br>
       Password: <input type="password" name="reg_password" id="reg_password"><br>

            <input type="submit" id="submit">
         </form>
    </html>

在表单提交之前执行javascript

4 个答案: