title: PHP date and time issue
body: <p>In php I set   </p>
  
  <pre><code>date_default_timezone_set("Asia/Calcutta");  
  </code></pre>
  
  <p>My system timezone is <code>(UTC+05:30) Chennai, Kolkata, Mumbai, New Delhi</code></p>
  
  <p>Both are same.<br>
  But when  I change the system date and time , the PHP returns the same date and time as sytem date and time .<br>
  ie) When I set system time as <strong>2013-07-10 11:00:00</strong>, then 
  PHP date function returns the same date time as <strong>2013-07-10 11:00:00</strong>. But the actual time is different.<br>
   I want the actual date and time from php not system date and time.<br>
  How can I implement this? If you have any idea please share.</p>