<code lang="PHP">
function daysBetweenDates($dateStart,$dateEnd) {
        // dateStart and dateEnd in the form of 'YYYY-MM-DD' 
	$dateStartArray = explode("-",$dateStart);
	$dateEndArray = explode("-",$dateEnd);
	
	$startYear = $dateStartArray[0];
	$startMonth = $dateStartArray[1];
	$startDay = $dateStartArray[2];
	
	$endYear = $dateEndArray[0];
	$endMonth = $dateEndArray[1];
	$endDay = $dateEndArray[2];
	
	//first convert to unix timestamp
	$init_date = mktime(12,0,0,$startMonth,$startDay,$startYear);
	$dest_date = mktime(12,0,0,$endMonth,$endDay,$endYear);

	$offset = $dest_date-$init_date; 

	$days = floor($offset/60/60/24); 
	return $days;
}
</code>