profile background customization using jQuery?

I wanted to know how to implement customization in your apps, like the design aspect, like tumblr, posterous and twitter, all use these customizatio开发者_Python百科n tools to allow their users to customize, do they have their own css file for each user, or is it pulled from the database, how does it work thanks?

p.s. if there is a plugin or class that helps with this, it will be greatly appreciated

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For each user in database, have stored css values:

and your have php file that generates css.

//css

background-image:url(<?php echo $user['background-image']; ?>);

variable $user comes from database