posting variable from php file to another php file - php

Question

I show similar threads, but could not get clear through them.
page1.php
<?php
$id = 1234;
//Post $id to page2.php
?>
page2.php
<?php
$user_id=$_POST['id']; //should receive id posted from page1.php
?>

Answer 1

Actually you are not sending the id parameter to your Page2.php
Page1.php
<?php
$id = 1234;
header("location:page2.php?id=$id");//Post $id to page2.php
?>
Page2.php
<?php
echo $user_id=$_GET['id']; //should receive id posted from page1.php
?>

Answer 2

You can use sessions for this also, to show you what your options are.
This works with a POST method (use all in one file for the form method)
Form method (page1.php)
<?php
session_start();
$id = $_SESSION["id"] = $_POST['id'];
if(isset($_POST["submit"])){
echo $id;
echo "<br>";
echo "<a href='page2.php'>Click to see session ID on next page</a>";
}
?>
<form action="" method="post">
Enter ID:
<input type="text" name="id">
<br>
<input type="submit" name="submit" value="Submit">
</form>
page2.php
<?php
session_start();
$user_id=$_SESSION["id"];
echo $user_id; // will echo 1234 if you entered "1234" in the previous page.
Regular session method (page1.php)
<?php
session_start();
$id = $_SESSION["id"] = "1234";
echo $id; // will echo 1234
page2.php
<?php
session_start();
$user_id=$_SESSION["id"];
echo $user_id; // will echo 1234
Footnotes:
You could then use the same (session) variable for a member's login area, database for example.
It is important to keep session_start(); included inside all pages using sessions, and at the top.
Should you be using a header() in conjunction with this, then you will need to add ob_start(); before session_start();
Otherwise (as Eitan stated in a comment) "$_SESSION value will be unresolvable."
header() example:
<?php
ob_start();
session_start();
$user_id=$_SESSION["id"];
if(isset($_SESSION["id"])){
header("Location: members_page.php");
exit;
}
else{
header("Location: login_page.php");
exit;
}
You could also replace: if(isset($_SESSION["id"])) with if(!empty($_SESSION["id"]))
To implement a logout page, you would need to use session_destroy();