Convert HTML 5 app to be offline

I have a single page app developed in Angular.js, PHP, MySQL that I need to be converted to have "offline" mode due to internet dropping in and out at times. The application is simple (4 pages) school attendance app. Application pulls the data (classroom, students booked for the day) from the server (php, mysql). Teacher then updates their attendance and it pushes back to server. All I need is a way to store data (approx 1mb) locally(indexDB storage limit is (5mb)) if the internet drops out and then it should push data back if the internet is back. I understand that all the html files and css needs to be cahed (manifest) as well for it to work. I just need a prototype of how it will work. Thanks