php pass parameter in url

Question

I have a form and a PHP function:

<?php

if(isset($_GET['sub'])) {
  var_dump($_REQUEST);
  die;
}
?>

<form action="index.php?a=12" method="get">
  <input name="sub" type="submit" value="Calc">
</form>

But when I click to submit I get nothing.

How can I pass variable a in URL (without any inputs) and why this method doesn't work?

Answer 1

You need a , but you get sub . It's problem. And you must use a for input . You can see difference in this code.

<?php
if(isset($_GET['a'])) {
var_dump($_REQUEST);die;
}
?>

<form action="index.php?a=12" method="get">
<input name="a" type="submit" value="Calc">
</form>

Output:

array (size=1) 'a' => string 'Calc' (length=4)

Answer 2

This method does not work because you put a not sub variable in URL, so I think you need to change to this :

<?php

if(isset($_GET['a'])) {
    var_dump($_REQUEST);
    die;
}
?>

Try to do a var_dump($_REQUEST); before your if to see what you have.

Answer 3

you have 2 options to send variables in the URL:

1. use a hyperlink

 <a href="index.php?a=12">Test!</a> 

2. Use a form with GET, and have the field as hidden.

 <form action="index.php" method="get"> <input name="a" type="hidden" value="12"> <input name="sub" type="submit" value="Calc"> </form>

You are mixing both methods, and the contents of the GET form, override your action.

Answer 4

Try this, instead of:

if(isset($_GET['sub'])) {

use:

if(isset($_GET["sub"))}