Enable GZip Compression

Gzip is the most popular and effective compression method currently available and generally reduces the response size by about 70%. Approximately 90% of today’s Internet traffic through browsers that claim to support gzip. Gzip is a server process that essentially compresses your files on the fly before transmission to the user. It is primarily used to compress text files such as HTML, CSS, and JavaScript with impressive results.

GZip method was used in earlier version of apache (before apache 1.3). But after that apache introduced deflate method which is not much effective as Gzip (But still it is very good). But GZip is no more supported after apache 1.3. So in now a days you must have Apache greater than 1.3 and if not you must upgrade to latest version.

To take an advantage of this compression facility you must have apache module mod_deflate enabled. To enable this module you just need to uncomment this module line from httpd.conf file.

Place this code in .htaccess

# Remove -- from < and > so it will look link < instead of <--

<--IfModule mod_deflate.c-->
# force deflate for mangled headers
<--IfModule mod_setenvif.c-->
<--IfModule mod_headers.c-->
SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)\s*,?\s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding
<--/IfModule-->
<--/IfModule-->

# HTML, TXT, CSS, JavaScript, JSON, XML, HTC:
<--IfModule filter_module-->
FilterDeclare   COMPRESS
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/html
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/css
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/plain
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/xml
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $text/x-component
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/javascript
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/json
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/xml
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/xhtml+xml
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/rss+xml
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/atom+xml
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/vnd.ms-fontobject
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $image/svg+xml
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $application/x-font-ttf
FilterProvider  COMPRESS  DEFLATE resp=Content-Type $font/opentype
FilterChain     COMPRESS
FilterProtocol  COMPRESS  DEFLATE change=yes;byteranges=no
<--/IfModule-->

<--IfModule !mod_filter.c-->
# Legacy versions of Apache
AddOutputFilterByType DEFLATE text/html text/plain text/css application/json
AddOutputFilterByType DEFLATE application/javascript
AddOutputFilterByType DEFLATE text/xml application/xml text/x-component
AddOutputFilterByType DEFLATE application/xhtml+xml application/rss+xml
AddOutputFilterByType DEFLATE application/atom+xml
AddOutputFilterByType DEFLATE image/svg+xml application/vnd.ms-fontobject
AddOutputFilterByType DEFLATE application/x-font-ttf font/opentype
<--/IfModule-->
<--/IfModule-->

If you can’t change your .htaccess file, you can try to use PHP to return compressed content. Give your HTML file a .php extension and add this code to the top:

In PHP:

<-- php 
if (substr_count($_SERVER['HTTP_ACCEPT_ENCODING'], 'gzip')) 
 ob_start("ob_gzhandler"); 
else 
 ob_start(); 
-->

Verify Your Compression:
http://www.gidnetwork.com/tools/gzip-test.php
http://www.whatsmyip.org/http-compression-test