A function for checking the current page call happened via SSL or not

check-for-ssl.php

<?php
function isSSL() {
    if (isset($_SERVER['HTTPS']) ) {
        if (!empty($_SERVER['HTTPS'])) {
            return true;
        }
        if (strtolower($_SERVER['HTTPS'] === "on") { // for IIS
            return true;
        }
    } elseif (isset($_SERVER['SERVER_PORT']) && $_SERVER['SERVER_PORT'] == 443) {
        return true;
    }
    return false;
}