How and when to notify user of AJAX call error/exception

Question

I'm working on a website in ASP.NET that loads the page, before doing an ajax call through javascript to get the actual data from the database (and show it inside a table most of the time). However, if something goes wrong with the ajax call, or there is an error adding/updating data, how should I notify the user about it?

• The easiest solution is of course to just show an alert, but I'm not sure if that's good user experience. Also in most browsers users can disable popup windows from a certain website, so if they do that they get 0 feedback at all when something goes wrong.
• Using a modal to get a more advanced alert.
• A separate page to display the error.
• ... Any other suggestions?

Giving the user feedback when an action failed upon submitting a form is pretty obvious. But if your website automatically updates the data by using ajax calls every x amount of time and it fails, should I notify the user too, or should I let it fail silently (considering the website is already there, they probably wouldn't notice)?

Thanks in advance!

Answer 1

Maybe you could enrich the tables (or other elements that need an AJAX call) with a visual clue that indicates a status:

• connecting with server
• loading / recieving data
• connected
• connection time-out
• fail
• etc.

So the element remains visible, but the indicator tells your users if the information they see is up to date of why there isn't any information at all. Much like when you're typing a e-mail in gmail and gmail can't connect to the server anymore. You can still type but there is a yellow bar that tells you, you can't send the e-mail or save your draft at the moment.

Answer 2

You can try something like this to notify user about failed attempt (you can change message to suit your requirements) and provide a refresh or reload option to query again.