Any one can tell me what the reason of this warning and how to fix it up...
Warning: Cannot modify header information - headers already sent by (output started at /home/ataulhab/public_html/tracking/update.php:3) in /home/ataulhab/public_html/tracking/update.php on line 31
here is the code
<?php include("dbconnection.php");?>
<?php
$update=mysql_query("UPDATE tracking SET origin='$_POST[origin]', pickup_date='$_POST[pickup_date]', shipper='$_POST[shipper]', consignee='$_POST[consignee]', quantity='$_POST[quantity]', commodity='$_POST[commodity]', weight='$_POST[weight]', flight_details='$_POST[flight_details]', present_status='$_POST[present_status]', received_by='$_POST[received_by]', received_on='$_POST[received_on]', received_at='$_POST[received_at]', remarks='$_POST[remarks]' WHERE hawb_no='$_POST[hawb_no]'");
if($update)
{
header ('Location:order_list.php');
}
?>