title: paypal do not return txn_id in mobile site
body: <p>I have using paypal in my desktop website and it worked. Below is my code:</p>
  
  <pre><code>&lt;?php
  ......
  echo '&lt;form name="form1" action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post"&gt;&lt;div&gt;
  &lt;input type="hidden" name="cmd" value="_xclick"&gt;
  &lt;input type="hidden" name="charset" value="UTF-8"&gt;
  &lt;input type="hidden" name="cancel_return" value="'.$host.'/my-order-history"&gt;
  &lt;input type="hidden" name="no_note" value="1"&gt;
  &lt;input type="hidden" name="no_shipping" value="1"&gt;
  &lt;input type="hidden" name="return" value="'.$host.'/payment-done?nid='.$node-&gt;nid.'&amp;order='.date("YmdHis",$time).'"&gt;
  &lt;input type="hidden" name="rm" value="2"&gt;
  &lt;input type="hidden" name="currency_code" value="HKD"&gt;
  &lt;input type="hidden" name="handling_cart" value="0.00"&gt;
  &lt;input type="hidden" name="invoice" value="'.date("YmdHis",$time).'"&gt;
  &lt;input type="hidden" name="tax_cart" value="0.00"&gt;
  &lt;input type="hidden" name="business" value="'.$paypal.'"&gt;
  &lt;input type="hidden" name="upload" value="1"&gt;
  &lt;input type="hidden" name="amount" value="'.$total_amount.'"&gt;
  &lt;input type="hidden" name="item_name" value="'.$company_name."-".date("YmdHis",$time).'"&gt;
  &lt;input id="go_pay" type="submit" name="next"  value="confirm" /&gt;
  &lt;/form&gt;';
  ......
  ?&gt;
  </code></pre>
  
  <p>and in payment-done page, I can get the txn_id with $_POST["txn_id"]. But When I use above code in my mobile website, I can pay with paypal by I can't get the txn_id in payment-done page. What can I do to change the code to work in mobile site?</p>
  
  <p>Thank you.</p>