form doesnt set variables when echoed - php

Try to set it as submit type

<button class=\"btn btn-success\" name=\"register\" value=\"Register\" type=\"submit\">Register</button>

Okay According To You're Question
Why if(isset($_POST['register']))is not isset or considered have a null value
Because You don't set The Value of the button Try This

<button class=\"btn btn-success\" value="save" name=\"register\">Register</button>

This Code Will Give $_POST['register'] a Save Value or same as $_POST['register'] = 'save'
Hope This Answer Help

To start with you need some information about the differences you can use.

isset()

isset — Determine if a variable is set and is not NULL

In other words, it returns true only when the variabble is not null.

Documentation:

• http://www.php.net/manual/en/function.isset.php

empty()

empty — Determine whether a variable is empty

In other words, it will return true if the variable is an empty string, false, array() (or []), NULL, 0, and an unset variable.

Documentation:

• http://www.php.net/manual/en/function.empty.php

Related to your code and your issue, it seems $_POST is not set, so you get false in return.

You can do a couple of things to check what is inside $_POST and what to do it it is empty.

While debugging always check what is inside your data. So for that you can use:

echo '<pre>';
var_dump($_POST);
echo '</pre>';

Documentation:

• https://www.php.net/manual/en/function.var-dump.php

Hopefully, you will receive an array like:

$array = [
        1 => 'one',
        2 => 'two',
        3 => 'three',
        4 => 'four',
        5 => 'five',
];

echo '<pre>';
var_dump($array);
echo '</pre>';
die;

Outcome:

array(5) {
  [1]=>
  string(3) "one"
  [2]=>
  string(3) "two"
  [3]=>
  string(5) "three"
  [4]=>
  string(4) "four"
  [5]=>
  string(4) "five"
}

Related to isset(), and to catch incase the array/string is empty you can do this:"

 $register = (isset($_POST['register']) ? 1 : 0);

In the code above $register will always be set. Read it like this:

• (isset($_POST['register'])) = 'If $_POST['register'] is set'
• ? = 'THEN DO THIS' (in our example it will become (int) 1).
• : = 'IF NOT THEN DO THAT' (In case $_POST['register'] is not set, $register becomes (int) 0)

If $register keeps staying empty, please reload your page. By filling in your format and send actually data within $_POST. It is possible if you press F5, the $_POST data disappears which means the data is empty.

Please let me know if this was somewhat useful or not. I rather to give you information so you can practice while doing, instead of getting clear code and copy paste this. If you have questions, let me know.