php 第二个如果验证不起作用

Question

如果验证不起作用，则为第二个 php

第二个如果是:$firstnameErr =“仅允许字母和空格”;不能直接工作，它会重定向到 success.php。

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<?php
    $firstname="";
    $firstnameErr="";
    
    if ($_SERVER['REQUEST_METHOD']== "POST") {
       $valid = true;
         
     if(empty($_POST["fname"]))
    {
        $firstnameErr="*firstname is Required";
        $valid=false;   
    }
    else
    {
    $firstname=test_input($POST["fname"]);
     if (!preg_match("/^[a-zA-Z ]*$/",$firstname))
           {
           $firstnameErr = "Only letters and white space allowed"; 
           }    
    } 
       
     //if valid then redirect
      if($valid){
          include 'database.php';
          echo '<META HTTP-EQUIV="Refresh" Content="0; URL=success.php">';    
        exit;
    //   header('Location: datasubmitted.php');
    //   exit();
      }  
    
    }
    
    function test_input($data)
    {
         $data = trim($data);
         $data = stripslashes($data);
         $data = htmlspecialchars($data);
         return $data;
    }
    
    ?>

Answer 1

当名字包含除字母和空格之外的额外字符时，您需要将 $valid 设置为 false。否则，无论它包含什么字符，它都会重定向到成功。

       $firstname=test_input($_POST["fname"]); //<-- changed this line. you have missed "_"
       if (!preg_match("/^[a-zA-Z ]*$/",$firstname))
       {
          $firstnameErr = "Only letters and white space allowed"; 
          $valid = false; //<-- Add this line
       }