regex - 正则表达式验证信息（仅限字母和数字）

Question

正则表达式验证信息

我尝试了以下方法：

if(preg_match("/[A-Za-z0-9]+/", $ingame_name) == TRUE){
     header("Location: newitem.php?username=". $ingame_name ."&email=". $email);
} else { 
    $invalidusername = '<font color=red>Oops, invalid username! Username
        may only contain numbers and letters.</font><br>'; 
}

哪个不起作用，还尝试翻转语句仍然不起作用...

我最后的尝试

if ($_REQUEST['do'] == 'submit')   
{
    $ingame_name= trim($_POST['ingame_name']);
    $email = trim($_POST['email']);

    if(eregi("/[A-Za-z0-9]+/", $ingame_name))
    {
    $invalidusername = '<font color=red>Oops, invalid username! Username may only contain numbers and letters.</font><br>';
    $ingame_name = 'invalid'; 
    }  
    if (eregi("^[a-zA-Z0-9_]+@[a-zA-Z0-9\-]+\.[a-zA-Z0-9\-\.]+$]", $email))
    { 
    $invalidemail =  '<font color=red>Oops, seems that you have an error with your email format.</font></br>';
    $email = 'invalid'; 
    }

    if ( $ingame_name = 'invalid'  || $email = 'invalid') 
    { 
    /* do nothin */ 
    } 
    else
    {  
    header("Location: item.php?username=". $ingame_name ."&email=". $email); 
    }    
} 

似乎没有任何工作，

Answer 1

试试这个：

<?php
$valid_submit = ($_REQUEST && isset($_REQUEST['do']) && $_REQUEST['do'] == 'submit') ? true : false;
if ($valid_submit) {
    $ingame_name= ($_POST && isset($_POST['ingame_name'])) ? trim($_POST['ingame_name']) : '';
    $email= ($_POST && isset($_POST['email'])) ? trim($_POST['email']) : '';
    $invalidusername = '';
    $invalidemail =  '';
    if(!preg_match("/^[A-Za-z0-9]+$/", $ingame_name)) {
      $invalidusername = '<font color=red>Oops, invalid username! Username may only contain numbers and letters.</font><br>';
      $ingame_name = 'invalid'; 
    }
    // This is a much more efficient method to validate email addresses
    if (!filter_var($email, FILTER_VALIDATE_EMAIL)) { 
      $invalidemail =  '<font color=red>Oops, seems that you have an error with your email format.</font></br>';
      $email = 'invalid'; 
    }
    if ( $ingame_name != 'invalid' && $email != 'invalid') {
      $location = 'item.php?username=' . $ingame_name . '&email=' . $email;
      header("Location: $location"); 
    } 
    else {
      //echo $invalidusername . $invalidemail;
    }    
}