扩展php中的时间函数DateDiff和DateAdd
function DateDiff($part, $begin, $end)
{
$diff = strtotime($end) - strtotime($begin);
switch($part)
{
case "y": $retval = bcdiv($diff, (60 * 60 * 24 * 365)); break;
case "m": $retval = bcdiv($diff, (60 * 60 * 24 * 30)); break;
case "w": $retval = bcdiv($diff, (60 * 60 *
