How to slow down and control the loading speed of a webpage?

I know that this question is unusual and it's also harder than it sounds so kudos to anyone who tries to answer it.

I want to slow down the speed with which a webpage loads. If possible I want to control how slowly that webpage loads (is seconds). I have some idea of how to do it with javascript, but I want to be able to do it with PHP only if possible, because not every user has javascript enabled.

Do you know any tricks that can do such a thing?

 

http://www.uselessapplications.com/en/Application/FirefoxThrottle.aspx

 

int sleep ( int $seconds )

http://php.net/manual/en/function.sleep.php