Save input for next input - php

Question

Well, I have this code:
<form name="download" id="download" method="post" enctype="multipart/form-data">
<div>
<label for="beginning_date"><span class="required">*</span> Beginning Date: </label>
<input type="text" size="30" id="beginning_date" name="beginning_date" value="<?php echo date("d.m.Y"); ?>" required="required" />
</div>
<input type="submit" value="Next" name="next"/>
</form>
and php..
if(array_key_exists('next', $_POST))
{
if (preg_match('/^\d{1,2}\.\d{1,2}\.\d{4}$/', $date))
{
//the code continues...
}
else
{
echo "Wrong formation <br />";
}
}
This is a long form, and I want that if someone inputs a date like this "02.03.20322", and the error appears, they don't have to start over to fill the form... the form already appears with the "fills field"...
I've already tried like these:
<input type="text" size="30" id="beginning_date" name="beginning_date" value="<?php if (isset($date)) { echo $date; } else { echo date("d.m.Y"); } ?>" required="required" />
but... no changes :(

Answer 1

Looking at your code, there simply is no $date so what you should check for is the existence of $_POST['beginning_date'] instead of $date like so:
<input type="text" size="30" id="beginning_date" name="beginning_date" value="<?php if (isset($_POST['beginning_date'])) { echo $_POST['beginning_date']; } else { echo date("d.m.Y"); } ?>" required="required" />

Answer 2

When using method post the submitted values of the user go into the $_POST array. The name of the form element is used as key.
So to retrieve the date submitted by the user, you should use:
$_POST['beginning_date']

Answer 3

Just save it in $_SESSION,
at the top of page or anywhere in your action.php:
if (isset($_POST)){
$_SESSION['date'] = $_POST['beginning_date'];
}
and then:
<input type="text" size="30" id="beginning_date" name="beginning_date" value="<?php echo (isset($_SESSION['date'])) ? $_SESSION['date'] : date("d.m.Y");?>" required="required" />
Using session is useful in case that in the future you need to change your action page. but if you want to use post instead(for same page posting), just echo it:
<input type="text" size="30" id="beginning_date" name="beginning_date" value="<?php echo (isset($_POST['beginning_date'])) ? $_POST['beginning_date'] : date("d.m.Y"); ?>" required="required" />

Answer 4

php..
session_start();
if(array_key_exists('next', $_POST))
{
if (preg_match('/^\d{1,2}\.\d{1,2}\.\d{4}$/', $date))
{
//the code continues...
}
else{
echo "Wrong formation <br />";
$_SESSION['date']=$_POST['beginning_date'];
}
}
html..
<input type="text" size="30" id="beginning_date" name="beginning_date" value="<?php if
(isset($_SESSION['date'])) { echo $_SESSION['date'] } else { echo date("d.m.Y"); } ?>"
required="required" />