Increment PHP variable value by 1 when submit

Question

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;  
    }
?>

You need to store that variable somewhere, eg. File, Database or even Session. What you're doing will always show 1. — vee
– vee, Commented Jul 5, 2013 at 17:53
After this script is run, the variable $i is freed in memory (aka it's gone). The next time you execute the script, PHP has no idea what $i is until you set $i=0. So when you click submit it will always echo 1. — Caleb Taylor
– Caleb Taylor, Commented Jul 5, 2013 at 18:00

Community · Accepted Answer · 2017-05-23 10:29:28Z

5

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;  
}

edited May 23, 2017 at 10:29

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answered Jul 5, 2013 at 17:52

Anas

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Comments

Simón Urzúa · Accepted Answer · 2013-07-05 18:04:49Z

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

answered Jul 5, 2013 at 18:04

Simón Urzúa

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Comments

CodeAngry · Accepted Answer · 2013-07-05 17:52:51Z

1

var_dump($IsPost = !strcasecmp($_SERVER['REQUEST_METHOD'], 'POST'));

^ tells you if it's a post.

echo ++$i;

^ increments $I and then prints $I

echo $i++;

^ prints $I and then increments $I

empty($_POST['submit']); // or isset($_POST['submit']);

^ tells you if ['submit'] exists in $_POST without notices.

answered Jul 5, 2013 at 17:52

CodeAngry

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Comments

iTom · Accepted Answer · 2013-07-05 17:57:40Z

1

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

answered Jul 5, 2013 at 17:57

iTom

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