Question: Does PHP have global variables that can be modified by one running script and read by another?

Answer: 
You can use [$\_SESSION](http://php.net/manual/en/book.session.php), i.e.:

**script1.php**

```
<?php
session_start();
$_SESSION['myVar'] = "something";
?>

```

**script2.php**

```
<?php
session_start();
echo $_SESSION['myVar'];
//something
?>

```
Global variables are bad in most programming. They're especially bad in multithreaded/multiuser systems like webapps. Avoid. If you must use global variables (rather than global constants) put them in a database with transactions guarding updates.

Since you talk about different scripts though, it sounds like what you really want is a web application framework in a more application oriented language --- something like Django (python) or Rails (ruby). These let you think of your code much more like a cohesive PROGRAM, rather than a lot of loosely connected scripts that process web requests.