Check if PHP is installed on Apache or IIS Server?

Question

Is there a way to check if PHP is installed on an Apache or IIS server within the PHP environment itself?

If so, how?

Answer 1

The virtually most definitive answer possible (there are other similar possibilities) is:

function on_iis() {
    $sSoftware = strtolower( $_SERVER["SERVER_SOFTWARE"] );
    if ( strpos($sSoftware, "microsoft-iis") !== false )
        return true;
    else
        return false;
}

Now, just use on_iis() whenever you want to know.