Share the php code of Beibei's growth progress

function getDays() {
putenv("TZ=Asia/Chongqing");
$by = 2006;
$bm = 7;
$bd = 7;
$rday="";

$today = getdate();
$by = $today[year] - $by;
$bm = $today[mon] - $bm;
$bd = $today[mday] - $bd;
if ($bd < 0) {
$bd = 30 + $bd;
$bm--;
}
if ($bm < 0) {
$bm = 12 + $bm;
$by--;
}
#print $by."-".$bm."-".$bd;
if ($by > 0) {
$rday = $by . "years";
}
if ($bm == 0&&$bd == 0){
$rday .="Birthday";
}else{
if ($bm == 0){
$rday.="zero".$bd."day";
}elseif ($bd == 0){
$rday.=$bm."Moon full";
}else{
$rday.=$bm."month".$bd."day";
}
}
return $rday;
}