With a bit more code you can have it refresh every second, but I have a quick question first, do you want it to display your local server time, or the users local time?
Oh right. Normally you would have a time interval in the code itself. Can you modify the code? Or is it an iframe widget? @Pealco most likely can help here.
As I have several div that need update in a bloc, shall I write a different function for each div to be updated or can I call the function with an argument, i.e. the name of the php file to update the div?
Or, as an alternative, is there a chance to update an entire bloc?
If you have different values and you have different places is better to update each one, as if is not by this way, it will be simpler to you one of two solutions:
Have a iframe and change only one page in blocs app and the main page updates as the page is upgraded.
Or have a php with all the bloc and you call the php as an iframe, as this way you can create a script to affect element inside your php.