Testing the browser with PHP

As we start building up dynamic web pages with PHP we perhaps need to be able to test for the browser type in our pages, in any case, this is a great start to using variables and conditional statements within PHP pages. First we can use super globals to display the browser type.

<?php
 $user_agent = $_SERVER['HTTP_USER_AGENT'];
echo "$user_agent . <br>";
?>

We are accessing the super global here, $_SERVER, this is an array and we access the key HTTP_USER_AGENT. If we want to list the complete list of keys in $_SERVER we could use the function print_r:

<?php
echo “<pre>”;
print_r($_SERVER);
echo “</pre>”;
?>

Really though, we don’t just want to print information; lets add in some conditional statements to run different code for different browsers:

<?php
 $user_agent = $_SERVER['HTTP_USER_AGENT'] . "<br>";
 if (strpos($user_agent, 'Mozilla') !==false) {
    echo "Nice one <br>";
  } else {
   echo "Never mind <br>";
  }
?>

Using this code we test using the function strpos for Mozilla being present in the HTTP_USER_AGENT string. On Firefox we can see the postive affirmation:

As a starting point in learning PHP this makes a great start, soon we will be looking at how we can access LDAP directories and MySQL databases with code and formatting the pages with CSS.