Using a variable from another condition in PHP

Question

I have this code:

if(!isset($_GET[\"act\"]))
{
    $display->display(\"templates/install_main.html\");
    if(isset($_POST[\"proceed\"]))
    {
        $prefi         


        

Answer 1

PHP's variable scope is function-level. $prefix would be available in your second if() IF the other if()'s evaluated to true and actually executed that $prefix = ... code.

e.g.

if (true) {
    $foo = 'bar'; // always executes
}
if (false) {
    $baz = 'qux'; // never executes
}
echo $foo; // works just fine
echo $baz; // undefined variable, because $baz='qux' never executed.

Also note that PHP is not capable of time travel:

echo $x; // undefined variable;
$x = 'y';
echo $y; // spits out 'y'

"earlier" code will not have "later" variables available, because the code that actually creates/assigns values to those variables won't have executed yet.