Roquie

die(json_encode($jsonBox + array('redirect' => '/index.php/thanks'))); //мертвые с косами

if(response.hasOwnProperty('answer') && response.answer.ok == true) {
                $('form')[0].reset(); // обнулить форму с данными
                  setTimeout(function() {
                  window.location.href = redirect;
                  }, 1000);  // задержка в одну секунду перед редиректом
            }

<td><span class='text_gr time_str''>".time_left2($post['time']-$time)."</span></td>

//...
var work_number_string = document.getElementByClass('time_str').innerHTML;
//...

//...
document.getElementByClass('time_str').innerHTML =  "Осталось времени "+days+" д. "+hours+" ч. "+minutes+" мин. "+seconds+" сек.";
//...

$users = [
  'user1' => '123456'
];

// post request ...
$post = array_map('trim', $_POST);
if (isset($users[$post['login']]) && isset($post['password']) && $users[$post['login']] === $post['password'])
{
   //login successful
   $login = $post['login'];
   $password = $users[$post['login']];
}
else
{
   // paste error to session and redirect to ths page. use pattern PRG
   header('Location: http://example.com/redirect_to_this_page');
}

<form action="/" method="post">
        <label for="email">Email</label>
        <input type="text" name="email" placeholder="Email"/>
        <label for="password">Password</label>
        <input type="password" name="password" placeholder="Password"/>
        <label for="remember">
            <input type="checkbox" name="remember" checked/>
            Remember
        </label>

        <input type="hidden" name="csrf" value="token ..."/>
        <input type="submit" name="go" class="btn btn-success"/>
</form>

<form role="form">
  <div class="form-group">
    <label for="exampleInputEmail1">Email address</label>
    <input type="email" class="form-control" id="exampleInputEmail1" placeholder="Enter email">
  </div>
  <div class="form-group">
    <label for="exampleInputPassword1">Password</label>
    <input type="password" class="form-control" id="exampleInputPassword1" placeholder="Password">
  </div>
  <div class="form-group">
    <label for="exampleInputFile">File input</label>
    <input type="file" id="exampleInputFile">
    <p class="help-block">Example block-level help text here.</p>
  </div>
  <div class="checkbox">
    <label>
      <input type="checkbox"> Check me out
    </label>
  </div>
  <button type="submit" class="btn btn-default">Submit</button>
</form>