How to determine the number of months between two dates in php, php date_PHP tutorial

/**
 * @author injection(injection.mail@gmail.com)
* @var date1日期1
* @var date2 日期2
* @var tags 年月日之间的分隔符标记,默认为'-' 
* @return 相差的月份数量
* @example:
$date1 = "2003-08-11";
$date2 = "2008-11-06";
$monthNum = getMonthNum( $date1 , $date2 );
echo $monthNum;
*/
function getMonthNum( $date1, $date2, $tags='-' ){
 $date1 = explode($tags,$date1);
 $date2 = explode($tags,$date2);
 return abs($date1[0] - $date2[0]) * 12 + abs($date1[1] - $date2[1]);
}