PHP TUTORIALS - PHP Web Concepts

PHP Web Concepts

Identifying Browser & Platform


<html>
<body>
<?php
   $viewer = getenv( "HTTP_USER_AGENT" );
   $browser = "An unidentified browser";
   if( preg_match( "/MSIE/i", "$viewer" ) )
   {
      $browser = "Internet Explorer";
   }
   else if(  preg_match( "/Netscape/i", "$viewer" ) )
   {
      $browser = "Netscape";
   }
   else if(  preg_match( "/Mozilla/i", "$viewer" ) )
   {
      $browser = "Mozilla";
   }
   $platform = "An unidentified OS!";
   if( preg_match( "/Windows/i", "$viewer" ) )
   {
      $platform = "Windows!";
   }
   else if ( preg_match( "/Linux/i", "$viewer" ) )
   {
      $platform = "Linux!";
   }
   echo("You are using $browser on $platform");
?>
</body>
</html>

Display Images Randomly


<html>
<body>
<?php
  srand( microtime() * 1000000 );
  $num = rand( 1, 4 );
   
  switch( $num ) 
  {
  case 1: $image_file = "/home/images/alfa.jpg";
          break;
  case 2: $image_file = "/home/images/ferrari.jpg";
          break;
  case 3: $image_file = "/home/images/jaguar.jpg";
          break;
  case 4: $image_file = "/home/images/porsche.jpg";
          break;
  }
  echo "Random Image : <img src=$image_file />";
?>
</body>
</html>

Using HTML Forms


<?php
  if( $_POST["name"] || $_POST["age"] )
  {
     echo "Welcome ". $_POST['name']. "<br />";
     echo "You are ". $_POST['age']. " years old.";
     exit();
  }
?>
<html>
<body>
  <form action="<?php $_PHP_SELF ?>" method="POST">
  Name: <input type="text" name="name" />
  Age: <input type="text" name="age" />
  <input type="submit" />
  </form>
</body>
</html>

Browser Redirection


<?php
  if( $_POST["location"] )
  {
     $location = $_POST["location"];
     header( "Location:$location" );
     exit();
  }
?>
<html>
<body>
   <p>Choose a site to visit :</p>
   <form action="<?php $_PHP_SELF ?>" method="POST">
   <select name="location">
      <option value="http://w3c.org">
            World Wise Web Consortium
      </option>
      <option value="http://www.google.com">
            Google Search Page
      </option>
   </select>
   <input type="submit" />
   </form>
</body>
</html>

Displaying "File Download" Dialog Box


#!/usr/bin/perl

# HTTP Header
print "Content-Type:application/octet-stream; name=\"FileName\"\r\n";
print "Content-Disposition: attachment; filename=\"FileName\"\r\n\n";

# Actual File Content
open( FILE, "<FileName" );
while(read(FILE, $buffer, 100) )
{
   print("$buffer");
}