How to continue incrementing the value of a variable even after a page is reloaded?

Question

I wanted to add +1 in the variable $a every time the page is loaded.

I’ve used the code:

  $a = ++$a;
  echo $a

and also the:

  $a = $a++;
  echo $a

But it only adds once, and when I refresh the page, it doesn’t add anything else. Someone can give me a hint?

Answer 1

$txt="";
$arquivo="";
$visitas="";

    $txt        = "contador.txt";
    $arquivo    = fopen($txt,"a+");
    $visitas    = fgets($arquivo,1024);
    fclose($arquivo);

    $arquivo    = fopen($txt,"r+");
    $visitas    = $visitas + 1;
    fwrite($arquivo,$visitas);
    fclose($arquivo);  


    echo "Esta página foi visitada $visitas vezes";

The function fopen opens the specified file in the variable $txt.

The way r+ opens for reading and writing; places the file pointer at the beginning of the file.

The function fgets returns a row of an open file with the specified length (optional - specifies the number of bytes to read). Default is 1024 bytes.

The function fwrite allows writing to files,

This answer answers the author’s comment in David Santos' reply.

Voce could give me an example of how to do this to save to a txt file - Henrique Romulo 9/07 at 2:44

Answer 2

As was said by David Santos, when reloading the page the values are not saved. They are recorded there only at runtime, after that they are removed from memory.

In PHP, there are several ways to maintain values. A two most common for your case would be the use of Session or Cookies.

I would choose to use the session. Sessions maintain a bridge between client and server, allowing you to save specific values for each client (browser) that loads your page.

In your case, the variable $_SESSION (as quoted in one of the answers, but without any explanation as to what it would be).

Behold:

// inicia a sessão. Deve ser colocado antes de todo o código de saída para o 
//navegador e antes de usar a variável super global `$_SESSION

session_start();

// Se existir o índice 'a', incrementa. Se não, define 0  
if (isset($_SESSION['a'])) {

  $_SESSION['a']++;

} else {

  $_SESSION['a'] = 0;

}

// imprime o valor
var_dump($_SESSION['a']);

The above code will work as follows: $_SESSION will be stored on the server, with a unique identification for the client (browser, which is registered in a Cookie). No if we have the isset defining whether the index 'a' exists in the array of $_SESSION. If it exists, it increases the values. But if it does not exist, we define that it will be 0.

Thus, every time the page is reloaded, the value will also be modified and you will be saved in the session.

See More:

• Work with Session without cookies to prevent session theft

Here is an explanation about the fact that every Session uses Cookies

• How the session works in web browsers?

Sessions are used a lot to log in users:

• What is the best way to create a PHP login system

• What to save to a login session?

User counter

In my humble opinion, if you want to do a user counter, as has been pointed out in some comments, I think the best way is to use a database.

• How to write values to the MYSQL database using PHP?

Answer 3

The script stores the values of the variables only at runtime, after which the space in the memory occupied by them is released. Every time you refresh the page the script goes back to its original state.

If you want to save the value of a variable even after updating the page, you will need to save the value of it in a place external to the file, for example : xml, database, txt, among others...

Answer 4

It’s easy, try using the code below:

<?php

if(isset($_SESSION['a'])) {
    $_SESSION['a'] += 1;
} else {
    session_start();

    $_SESSION['a'] = 1;
}

echo $_SESSION['a'];