make a if statement run only when submit button is clicked - php

Question

Here i have a form and some php code to run only when submit button is clicked.But the "IF" block run as soon as the page reloads.As if the $_POST array is not empty.I can try with a single element,like !empty($_POST['name']).But i want to test on universal $_POST array.How can i do it?
<?php
require_once 'input.php';
if(Input::exists()){
print_r($_POST);
$arr=array('ball');
echo $arr[0];
}
?>
<form action='' method='POST'>
name:<input type='text' name='name' ></br>
<input type='submit' value='submit'>
</form>
input.php file:
class Input{
public static function exists($type='post'){
switch($type){
case 'post':
return (!empty($_POST))?true:false;
break;
default:
return (!empty($_GET))?true:false;
brek;
}
}
}

Answer 1

Why do you need the Input class? Just do this:
if ($_POST['name']) {
print_r($_POST);
$arr=array('ball');
echo $arr[0];
}

Answer 2

I suggest you add a name to your submit button
<input type='submit' name='submit' value='submit'>
if(isset($_POST['submit']))
{
php code goes here this will only run when submit btn has been clicked
}

Answer 3

If you want a form to submit data to itself omit the action attribute
The input class is incredibly overkill, but I suppose if you want to use it then we can make it work.
Change the Input class to look something like this...
class Input {
public static function exists($type='post') {
if ($type == 'post' && count($_POST) > 0)
return true;
else if ($type == 'get' && count($_GET) > 0)
return true;
}
}
I frankly hate switch statements and this should work just fine. Once again, I think the Input class is overkill.