function time_elapsed_string($datetime) {
$now = new DateTime;
$ago = new DateTime($datetime);
$diff = $now->diff($ago);
if ($diff->d > 0) {
return $diff->d . ' day' . ($diff->d > 1 ? 's' : '') . ' ago';
}
if ($diff->h > 0) {
return $diff->h . ' hour' . ($diff->h > 1 ? 's' : '') . ' ago';
}
if ($diff->i > 0) {
return $diff->i . ' minute' . ($diff->i > 1 ? 's' : '') . ' ago';
}
return 'just now';
} 