A PHP Error was encountered

Severity: Notice

Message: Undefined index: HTTP_REFERER

Filename: controllers/Home.php

Line Number: 429

Backtrace:

File: /var/www/online_2017/application/controllers/Home.php
Line: 429
Function: _error_handler

File: /var/www/online_2017/index.php
Line: 315
Function: require_once