Create a Mobile Website/Webapp which saves form data in a database when online or offline (and syncs back when connected)

I need a webapp which is basically a form with a series of questions with dropdown answers, some free text fields, a date selector and a photo import/taking function. When the user presses the submit button it saves the data in a database for later reporting then reloads a blank form for the next entry (confirming to the user that the details are stored). I don't mind how this is implemented, although my hosting is on 1&1 business unlimited package (PHP & MySQL) so it will need to run from there if possible. This app needs to work offline incase the user is in a no-wifi area, but the data needs to be stored and sync back to the online database when they reconnect. The user will then need to be able to generate & print a report on any aspect of the data, the report can also be exported as an excel or csv format for the user to manipulate There will also be the need for a back office area where an admin can customise the questions/answers, administrate users of the system etc. User details could be: Name, job title, company, contact number, email address (use this as username), password Could the app have a very long time before timeout / perpetual until logout. On the attached file, row 1 is the section headings, row 2 is the query to be completed, the rows below are the form fields, where there are multiple rows, these are the dropdown options.