Use GZip compression on your PHP files

gzip_footer.php

<?php
  $gzip_contents = ob_get_contents();
  ob_end_clean();

  $gzip_size = strlen($gzip_contents);
  $gzip_crc = crc32($gzip_contents);

  $gzip_contents = gzcompress($gzip_contents, 9);
  $gzip_contents = substr($gzip_contents, 0, strlen($gzip_contents) - 4);

  echo "\x1f\x8b\x08\x00\x00\x00\x00\x00";
  echo $gzip_contents;
  echo pack('V', $gzip_crc);
  echo pack('V', $gzip_size);
?>

gzip_header.php

<?php
$phpver = phpversion();
$useragent = (isset($_SERVER["HTTP_USER_AGENT"]) ) ? $_SERVER["HTTP_USER_AGENT"] : $HTTP_USER_AGENT;

if ( $phpver >= '4.0.4pl1' && ( strstr($useragent,'compatible') || strstr($useragent,'Gecko') ) ) {
   if ( extension_loaded('zlib') ) {
     ob_start('ob_gzhandler');
   }
} else if ( $phpver > '4.0' ) {
  if ( strstr($HTTP_SERVER_VARS['HTTP_ACCEPT_ENCODING'], 'gzip') ) {
    if ( extension_loaded('zlib') ) {
       $do_gzip_compress = true;
       ob_start();
       ob_implicit_flush(0);
       header('Content-Encoding: gzip');
     }
   }
}
?>

use.php

<?php
include('gzip_header.php');
include('your_template_file.php');
include('gzip_footer.php');
?>