php increment variable value with 1 when submit

Question

Hi I am new in php and started learning. I am trying to increment variable value with 1 when submit button is pressed.

My Code:

<?php
    $i=0;
    if($_POST['submit']){
        echo $i+1;  
    }
?>

Thanks

Answer 1

You're variable $i should be stored in session for example, so it won't lost its value when you submit the form. (You can check this answer Is PHP or PHP based web framework stateful or stateless?)

Also when your script is executed, the first thing you do is $i = 0; so whenever you execute it, you reinitialize the variable to 0.

session_start();

// if your variable is not yet defined, you assigned it with 0
if (isset($_SESSION['myVariable']))
{
    $_SESSION['myVariable'] = 0;
}

if($_POST['submit'])
{
    echo $_SESSION['myVariable'] +1;  
}

Answer 2

<?php
session_start();

    if($_POST['submit']){
        $_SESSION['i'] = isset($_SESSION['i']) ? ++$_SESSION['i'] : 0;
        echo $_SESSION['i'];
    }
?>

This will remember the last value between pages