>>>>I am working on a web page that will be used to update on-hand quantity of parts in a stock room. The page is very simple: it has a text box Part No and a text box Quantity. The user will scan or type in the Part No text box and then enter the current on-hand quantity in the Quantity box. Then user clicks on Submit button. Submit button will call a stored procedure that will update the database table(s).
>>>>
>>>>The program will work in a company Wi-Fi. But it is possible that for a short period (or maybe longer) the Wi-Fi signal will be dropped. So, if the connection is dropped, - ideally - (I would need to check it before calling the stored procedure) I would store the values in the Local Storage. Then, when connection is restored the data from the Local Storage should be processed (transparent to the user).
>>>>
>>>>How could this be done, conceptually? That is, how would a program/page call a stored procedure for every pair of values in the Local Storage?
>>>>TIA
>>>
>>>Something like:

saveEntry(partno, quan) {
>>>            var entry = { PartNo: partno, Quan: quan };
>>>            if (localStorage['entries'] === undefined) {
>>>                var entries = new Array;
>>>            } else {
>>>                entries = JSON.parse(localStorage['entries']);
>>>            }
>>>            entries.push(entry);
>>>            localStorage['entries'] = JSON.stringify(entries);
>>>            if (window.navigator.onLine) {
>>>                //Send entries array to server
>>>                //On success:
>>>                localStorage['entries'] = JSON.stringify(new Array);
>>>            }
>>>        }

This would send when a new entry was added. If you wanted to send when a connection became available you could add a watch on window.navigator.online and send from there....
>>
>>Thank you, Viv. I will try your code. Do I understand that, since you can write this code off the top of your head, you have used Local Storage and it is more or less reliable?
>
>I've been working on an app that's used mainly offline. I'm storing half a dozen object collections in localStorage (sometimes up to 300-400 items in total) and it's been fine. Only risk is that the user clears the browser history whilst there's still stuff waiting to be uploaded.
>
>Since I'm mainly offline I have a 'Upload' button (which is only enabled when there's a connection) and the user pushes data up when they want. Bear in mind that when you do have a 'online' status it doesn't necessarily mean you can connect to the server - only clear localStorage after a successful upload.

Thank you very much. I am taking notes of all your suggestions. Of course I know you are working with MVC and I am still in the 19th century technology of ASP.NET Web Forms :)