added login and logout

start.php

@@ -0,0 +1,28 @@
+<?php
+    
+    // Allow from any origin
+    if (isset($_SERVER['HTTP_ORIGIN'])) {
+        // Decide if the origin in $_SERVER['HTTP_ORIGIN'] is one
+        // you want to allow, and if so:
+        header("Access-Control-Allow-Origin: {$_SERVER['HTTP_ORIGIN']}");
+        header('Access-Control-Allow-Credentials: true');
+        header('Access-Control-Max-Age: 86400');    // cache for 1 day
+    }
+    
+    // Access-Control headers are received during OPTIONS requests
+    if ($_SERVER['REQUEST_METHOD'] == 'OPTIONS') {
+        
+        if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_METHOD']))
+            // may also be using PUT, PATCH, HEAD etc
+            header("Access-Control-Allow-Methods: GET, POST, OPTIONS");
+        
+        if (isset($_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']))
+            header("Access-Control-Allow-Headers: {$_SERVER['HTTP_ACCESS_CONTROL_REQUEST_HEADERS']}");
+    
+        exit(0);
+    }
+
+    session_start();
+    if(!isset($_SESSION["email"])) echo json_encode(false);
+    else echo json_encode(true);
+?>