>>>>>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 :)

Hardly using MVC at all - most of my pages are static HTML with data over WebApi......