form not always submitting. and i need a script to check if device is connected to internet before submiting

i do have a form where we perform car inspections with it. sometimes form is not submitting. it says success but when i check, it did not save in database. so i need someone to check and fix issue for me. one possibility is that due that we go outside to check the car, maybe the tablet device lost internet connection. and when we come back inside store, and submit, maybe it does not work when i upload form. so i need also a script to check if everything is oke (internet connection) before allowing to submit form. if no internet connection found, pop up a nice window telling me that. in either way i need the form to submit always when there is internet available so we dont loose informations that we filled in. the form is html, php and simple javascript. i need this as soon as possible so, bid only if you can start now and finish today, my budget is $25