Compression is a simple, effective way to save bandwidth and speed up your site.HTTP compression is a capability that can be built into web servers and web clients to make better use of available bandwidth, and provide faster transmission speeds between both. HTTP data is compressed before it is sent from the server: compliant browsers will announce what methods are supported to the server before downloading the correct format; browsers that do not support compliant compression method will download uncompressed data. The most common compression schemas include gzip and deflate, however a full list of available schemas is maintained by IANA. Additionally, it is known that third parties develop new methods and include them in their products (e.g. the Google SDCH schema implemented in Google Chrome browser and used on certain Google servers). To enable compression in php using deflate, just add the following lines in your htaccess file.
Deflate is quick and works, so I use it; use mod_gzip if that floats your boat. In either case, Apache checks if the browser sent the “Accept-encoding” header and returns the compressed or regular version of the file. However, some older browsers may have trouble (more below) and there are special directives you can add to correct this.