MSISDN Using Wifi/Mobile internet

Hi All, We are looking forward to get user's mobile number using MSISDN. Usually this is done by passing the headers in PHP and obtaining this over mobile internet when the mobile subscriber sends this information. We would want to know if this is possible via wifi as well? If so we need a HTML page which when users lands using a mobile device, will collect his mobile number. This is purely for advertising. Note:- No pop ups for permissions needs to be asked. This needs to be purely done using Http headers.