PHP templating and variable scope

I think you are not exactly understanding what is going on. Page 1 should probably be doing the echoing. So you include page 2 and the foo function is now available. You need to call it so that it actually executes. Use the global keyword to bring a global variable into the function scope. Then you can echo it.

page1:

include "page2.php";
foo();
echo $test;

page 2:

function foo()
{
    global $test;
    $test =1;

}

Variables in a function are not seen outside of them when they are not global. But an include in a function should be seen inside the second file.

$test="Big thing";
echo "before testFoo=".$test;

// now call the function testFoo();

testFoo();

echo "after testFoo=".$test;
Result : *after testFoo=Big thing*

function testFoo(){

  // the varuiable $test is not known in the function as it's not global

  echo "in testFoo before modification =".$test;

  // Result :*Notice: Undefined variable: test in test.php 
  // in testFoo before modification =*

  // now inside the function define a variable test. 

  $test="Tooo Big thing";
  echo "in testFoo before include =".$test;

  // Result :*in testFoo before include =Tooo Big thing*

  // now including the file test2.php

  include('test2.php');

  echo "in testFoo after include =".$test;

  // we are still in the function testFoo() so we can see the result of   test2.php
 //  Result :in testFoo after include =small thing

  }

in test2.php

echo $test;
/* Result : Tooo Big thing
   as we are still in testFoo() we know $test
   now modify $test
 */
$test = "small thing";

I hope that made the things more clear.