PHP - Rearrange Input Date From Dd.mm.yyyy To Yyyy.mm.dd

if(!function_exists('checkdate'))
{
	function checkdate($date, $checkyear, $currentmonth)
	{
		if($checkyear == 0)//if it is not a leap year
		{
			// if current month is february
			if($currentmonth == 2)
			{
				if(!preg_match("/^(20)\d\d[-](0[1-9]|1[012])[-](0[1-9]|1[0-9]|2[0-8])$/", $date))
				{
					// set error for date field
					return ($error = 'Invalid Date!');
				}
				return ($error = 'valid Date!');
			}
			// if current months are april, june, september or november
			elseif($currentmonth == 4 || $currentmonth == 6 || $currentmonth == 9 || $currentmonth ==11)
			{
				if(!preg_match("/^(20)\d\d[-](0[1-9]|1[012])[-](0[1-9]|1[0-9]|2[0-8]|3[0])$/", $date))
				{
					// set error for date field
					return ($error = 'Invalid Date!');
				}
				return ($error = 'valid Date!');
			}
			else
			{	
				if(!preg_match("/^(20)\d\d[-](0[1-9]|1[012])[-](0[1-9]|[12][0-8]|3[01])$/", $date))
				{
					// set error for date field
					return ($error = 'Invalid Date!');
				}
				return ($error = 'valid Date!');
			}
		}
		elseif($checkyear == 1)//if it is a leap year
		{
			// if current month is february
			if($currentmonth == 2)
			{
				if(!preg_match("/^(20)\d\d[-](0[1-9]|1[012])[-](0[1-9]|1[0-9]|2[0-9])$/", $date))
				{
					// set error for date field
					return ($error = 'Invalid Date!');
				}
				return ($error = 'valid Date!');
			}
			// if current months are april, june, september or november
			elseif($currentmonth == 4 || $currentmonth == 6 || $currentmonth == 9 || $currentmonth ==11)
			{
				if(!preg_match("/^(20)\d\d[-](0[1-9]|1[012])[-](0[1-9]|1[0-9]|2[0-9]|3[0])$/", $date))
				{
					// set error for date field
					return ($error = 'Invalid Date!');
				}
				return ($error = 'valid Date!');
			}
			else
			{	
				if(!preg_match("/^(20)\d\d[-](0[1-9]|1[012])[-](0[1-9]|[12][0-9]|3[01])$/", $date))
				{
					// set error for date field
					return ($error = 'Invalid Date!');
				}
				return ($error = 'valid Date!');
			}
		
		}
	}
$todate = getdate();
$currentmonth = $todate['mon'];
$checkyear = date('L');
$date = 2014-02-31;
echo checkdate($date, $checkyear, $currentmonth);

Hi,

I have a job listing website which displays the closing date of applications using:

$expired_date

(This displays a date such as 31st December 2019)

I am trying to show a countdown/number of days left until the closing date.

I have put this together, but I can't get it to show the number of days.

                    <?php 
                    $expired_date = get_post_meta( $post->ID, '_job_expires', true );
                    $hide_expiration = get_post_meta( $post->ID, '_hide_expiration', true );
                    if(empty($hide_expiration )) {
                        if(!empty($expired_date)) { ?>
                                <span><?php echo date_i18n( get_option( 'date_format' ), strtotime( get_post_meta( $post->ID, '_job_expires', true ) ) ) ?></span>
                    
                    <?php
                                        $datetime1 = new DateTime($expired_date);
                                        $datetime2 = date('d');
                                        $interval = $datetime1->diff($datetime2);
                                        echo $interval->d;

                     ?>
                        <?php }
                    } 
                    ?>

Can anyone help me with what I have wrong?

Many thanks