How can i Avoid Timeout for Long data entry form.

Question

How can i Avoid Timeout for Long data entry form. I have tried to set timeout in web.config, but no success. I have a website in which data entry form can take long time to fill in necessary information. By the time user is done with filling information, website timeout occur and user is logged out. Anyone has suggestion to tackle this situation in best efficient manner. I would also appreciate suggestion for how to do auto saving of data entry form, so that if user can fill in data at his convenience, something like gmail draft. Every suggestions are welcome. Thanks