Anyway to have a webpage regularly poll another

[JeffP]

Is it possible to have a webpage regularly check another website for some
particular data and then to display it in window if it exists?

Basically, I want a snippet of java script that can be placed in a page that
every so many seconds checks another website, which reads data in a
database, to see if a record has been added. If it has to then give the user
a response in another window where they can see that data and respond.

I am not well up on java script so more detail is better.

Thanks
Jeff