compress string

[eluser]duy31187[/eluser]
I'm new to codeigniter. after finished my first website.I have a questions:
I made a forum. so when there is someone comments,I want to compress it before send from client to server.but i don't know how to do it?
2.I have a textarea to comment.I want to keep comment look like user input.How can i do it?

[eluser]umefarooq[/eluser]
here its the link you can use to compress a string

compress string
http://www.php.net/manual/en/function.gzcompress.php

uncompress string
http://www.php.net/manual/en/function.gzuncompress.php