<?php
$city = $_GET['city'];
?>
<h1>Welcome to Population Data Online</h1>
<?
$cities = array(
  'Philadelphia' => 1548000,
  'New York' => 8337000,
  'Los Angeles' => 3858000,
  'Seattle' => 634535,
  'Boston' => 636479,
);
if ($city && isset($cities[$city])) {
  print '<p>The population of <strong>' . $city . '</strong> is <strong>' . $cities[$city] . '</strong></p>';
}

?>
<h2>Our Cities</h2>
<ul>
<?php
  foreach ($cities as $name => $value) {
    print '<li><a href="/jody/population.php?city=' . $name  . '">' . $name
    . '</a></li>';
  }
?>
</ul>