PHP Pocket Reference

Web-Related Variables

PHP automatically creates global variables for all the data it receives in an HTTP request. This can include GET data, POST data, cookie data, and environment variables. Say you have an HTML form that looks as follows:

<FORM ACTION="test.php3" METHOD="POST">
<INPUT TYPE=text NAME=var>
</FORM>

When the form is submitted to the test.php3 file, the $var variable within that file is set to whatever the user entered in the text field.

A variable can also be set in a URL like this:

http://your.server/test.php3?var=Hello+World

When the request for this URL is processed, the $var variable is set for the test.php3 page.

Any environment variables present in your web server’s configuration are also made available, along with any CGI-style variables your web server might set. The actual set of variables varies between different web servers. The best way to get a list of these variables is to use PHP’s special information tag. Put the following code in a page and load the page in your browser:

<? phpinfo(  ) ?>

You should see a page with quite a bit of information about PHP and the machine it is running on. There is a table that describes each of the extensions currently enabled in PHP. Another table shows the current values of all the various configuration directives from your php3.ini file. Following those two tables are more tables showing the regular environment variables, the special PHP internal variables, and the special environment variables that your web server has ...