Getting input value and put it in a variable PHP - php

Question

I have a problem of getting the value of an input element. Thanks in advance for help! This is the sample code:
<form action="#" method="POST">
<input name="X" value="3" />
<?php
//question: how can I put the value of input in a variable
//$_POST['X']; isn't applicable since I am in the same form.
?>
</form>

Answer 1

<form action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" method="POST">
<input name="X" value="3" />
<input type="submit" value="Submit">
</form>
<?php
if(isset($_POST['X']) == true){
echo $_POST['X'];
}
?>

Answer 2

First of all submitting a form on its own page is a bad practice because whenever you reload the page the form will submit everytime.
Best approach is that you set the action attribute of form to another file or link.
fileOne.php (where your form is located):
<form action="anotherfile.php" method="POST">
<input name="X" value="3" />
<button type="submit" name="submitForm">Submit</button>
</form>
Then in anotherfile.php you will do this:
$check = $_POST["submitForm"];
If(isset($check))
{
$myInputValue = $_POST["X"];
header("Location: fileOne.php/?val".$myInputValue);
}
Then in fileOne.php you can get the variable and its value which is sent via link in the browser like this:
$getInputValue = $_GET["val"];
Now you can echo out the $getInputValue variable wherever you want.
If the the information is not sensitive this is the best approach you got. But if it is, try saving that value in the session and retrieving in the file where you want. I hope it helps. Typed code via app so it might throw an error. But i think this code will work fine. Good luck!