[PHP] calculate length between date to date

[[EMAIL PROTECTED]]

Hi all
I have 2 variables here that store date start and date end, I want to compare the 
lenght between the start date and the end date, how would I do that?
$dateStart = "$year" . "$mon" . "$date" ; ( for instance, it will return "20010102")
$dateEnd = "$yearEnd" . "$monEnd" . "$dateEnd" ; ( for instance, it will return 
"20010201")

How do I calculate the length between those 2 variables?
Jack
[EMAIL PROTECTED]
"There is nothing more rewarding than reaching the goal you set for yourself"