Example of loading data dynamically with AJAX. Percentage change in GDP (source: Eurostat). Click the buttons below:
The data is fetched over HTTP, in this case directly from text files. Usually the URL would point to some web server handler (e.g. a PHP page or Java/.NET/Python/Ruby on Rails handler) that extracts it from a database and serializes it to JSON.
[ see data ]
[ see data ]
[ see data ]
If you combine AJAX with setTimeout, you can poll the server for new data.