How to convert timestamp to html date input field value PHP - php

Question

In my code, here is how i convert html date field values to unix timestamp before inserting to MySQL db which works fine:
//HTML Code:
<div class="form-group">
From:
<input type="date" name="dateFrom" value="<?php echo date('Y-m-d'); ?>" required/>
</div>
<div class="form-group">
To:
<input type="date" name="dateTo" value="<?php echo date('Y-m-d'); ?>" required/>
</div>
//PHP Code to convert to Time Stamp:
<?php $post->unix_stamp = strtotime($_POST['dateFrom']);
$post->unix_stamp_ex = strtotime($_POST['dateTo']);
$post->save(); ?>
How do i convert the unix timestamp back to html input date value for editing? What i've tried:
<input type="date" name="dateTo" value="<?php echo date("Y-m-d\TH:i:s",$post->unix_stamp_ex); ?>" required/>
Where $post->unix_stamp_ex is the unix timestamp value. (doesn't work for me, shows dd/mm/yyyy instead). My problem is how to get the underlying value, to display in the date input so users can edit it

Answer 1

The reason your input is showing a placeholder 'dd/mm/yyyy' is because it cannot read the format you gave it. It can't work with time, so you need to remove it from your code:
value="<?php echo date('Y-m-d',$post->unix_stamp_ex); ?>"
This will show the date in the input.
Also, mind that the displayed value will differ from the actual value format, as per my comment and RoussKS' answer.

Answer 2

According to Mozilla Developer docs for input type date
The displayed date format will differ from the actual value — the displayed date is formatted based on the locale of the user's browser, but the parsed value is always formatted yyyy-mm-dd.
[edit]
Just noticed the comment response, was typing as El_Vanja commented
[/edit]

Answer 3

Brother, I am able to convert the database string back to readable date time using the following method.
Solutions
$databaseTime = '2020-03-22 09:45:48';
$date = strtotime($databaseTime);
echo "DatabaseTime: " . $databaseTime . "<br>";
echo "Date in epoch: ".$date."<br>";
echo "Readable date: ".date("Y-m-d H:i:s",$date)."<br>";
Results
https://prnt.sc/rkmleq