php实现用已经过去多长时间的方式显示时间

//使用范例：
// timestamp to test:
// (could be from an database or something else)
$time = 1146722922;
// long if check:
if (time_is_older_than('30m',$time)){
print 'The given timestamp: ' . date('l dS of F Y h:i:s A',$time);
print " - is older than 30 minutes
n";
}
else {
print 'The given timestamp: ' . date('l dS of F Y h:i:s A',$time);
print " - is NOT older than 30 minutes
n";
}
// short checks:
if (time_is_older_than('10s',$time)){ print "Is older than 10 seconds
n"; }
if (time_is_older_than('200m',$time)){ print "Is older than 200 minutes
n"; }
if (time_is_older_than('2h',$time)){ print "Is older than 2 hours
n"; }
if (time_is_older_than('4d',$time)){ print "Is older than 4 days
n"; }
if (time_is_older_than('1y',$time)){ print "Is older than one year
n"; }