US Patent 9641591 Modifying web content at a client

Producing a modified document object model structure is disclosed. A desired webpage is requested. An alternative webpage is received in response to the request instead of an original version of the desired webpage to be rendered. The alternative webpage is processed. Program code included in the alternative webpage is utilized to request the original version of the desired webpage. The original version of the desired webpage is received. The modified document object model structure different from an original document object model structure corresponding to the received original version of the desired webpage is produced.