PHP variable scope question

I'm a beginner to PHP and trying to write a code, that does form validation. It's nothing fancy just testing it out. I just wrote a function that test the Age input text whether it's a number or not. If it isn't it stores an error in an array and then display that error in another page. I saw this method in a video tutorial , but couldn't do it myself. When i try to invoke that error (not numeric value in Age) it always shows me this error in my add.php page :

Notice: Undefined variable: errors in /home/rafael/www/RofaCorp/add/add.php on line 37

How do i declare a variable that can be accessed through my whole project ?

Here's my code :

• form_validation.php

<?php

function validate_number($number) {
   global $errors;
   if (is_numeric($number)) {
       return $number;
   }else {
       $errors[] = "Value must be number";        
   }

  开发者_开发技巧 if (!empty ($errors))
   {
       header("Location: ../add.php");
       exit;
   }
}

?>

• create_ind.php

  <?php require_once '../../include/connection.php'; ?>
  <?php require_once '../../include/form_validation.php'; ?>
  <?php require_once '../../include/functions_database_infoget.php'; ?>
  
  <?php
  $family_id = get_family_info_fam("id");
  $ind_name = mysql_real_escape_string($_POST["ind_name"]);
  $age = validate_number(mysql_real_escape_string($_POST["age"]));
  $gender = $_POST["gender"];
  $notes = mysql_real_escape_string($_POST["notes"]);
  
  
      $add_query = "INSERT INTO individual
                  ( g_id , ind_name , age , gender , notes) 
                  Values ( {$family_id} , '{$ind_name}' , {$age} , '{$gender}' ,     '{$notes}')";
          if(mysql_query($add_query , $connection)){
          header("Location: ../../main.php");
          exit;
      } else {echo "ERROR " . mysql_error() ; } 
  
  
  
  ?>
  
  <?php mysql_close($connection); ?>
  

• add.php (a portion of my code)

  <!--Main Content-->
  <section id="mainContent">
      <header>
          <h3>Select where to add new Family/Individual.</h3>
      </header>
      <article>
          <?php 
              if (count($errors) > 0) {
                  for($i=0 ; $i < count($errors) ; $i++){
                      echo "{$errors[$i]}" . "<br/>";
                  }
              }
          ?>
      </article>
  </section>
  

A global variable is only defined while your scripts are processing, as soon as you do header("Location: ../add.php"); you are loading a new page and all variables are lost. That´s what the error message is telling you, there is no variable $errors in add.php.

If you want your error message to persist between different page loads, a session variable is a good option (there are of course others like databases, etc.). Just start the session again in add.php and you have access to the variables stored in the session.

If it is shown in another page, use sessions. Will allow you to retrieve variables from other pages.

You can use this simple tut http://www.tizag.com/phpT/phpsessions.php