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>
  

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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.

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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