get date difference

https://stackoverflow.com/questions/13194322/php-regex-to-check-date-is-in-yyyy-mm-dd-format

$date="2012-09-12";

if (preg_match("/^[0-9]{4}-(0[1-9]|1[0-2])-(0[1-9]|[1-2][0-9]|3[0-1])$/",$date)) {
    return true;
} else {
    return false;
}

http://thisinterestsme.com/calculating-difference-dates-php/

<?php

 

//Our "then" date.

$then = "2009-02-04";

 

//Convert it into a timestamp.

$then = strtotime($then);

 

//Get the current timestamp.

$now = time();

 

//Calculate the difference.

$difference = $now - $then;

 

//Convert seconds into days.

$days = floor($difference / (60*60*24) );

 

echo $days;