How to get a date from a form in php?

sorry for my bad english…

I want to get a date from a a html form but I don’t success…

I have a form with an input *date *and an input *submit* :

<input type="date" placeholder="Enter date here" name="date">
<input type="submit" name="submit" value="Submit">

And I would like to get the date. So I tried this:

<form method="post">
              <input type="date" placeholder="Enter date here: 0000-00-00" name="date">
              <input type="submit" name="submit" value="Submit">
              
                <?php
                if (isset($_POST['date']))
                {
                    ?><script>alert(<?php echo $_POST['date']; ?>)</script> <?php
                }
                ?>
</form>

But when I click on submit, it displays a random date; example when I pick 2022-03-23, it displays 1996…

Someone can help me? I searched but I didn’t find a correct answer.

Thank You