how to update the page without refresh

Question

In Gmail when a new email is received, the page automaticly show the mail without refreshing, how this can be done?

Answer 1

You said it AJAX XMLHTTPRequest search for jQuery and ajax on the wiki, it's not sow tough stuff nowadays as it was 4-5 years ago, when we were using hidden iframes to simulate desktop application behaviour online.

This is a point to start: http://api.jquery.com/jQuery.ajax/

And this is the main idea: http://www.w3.org/TR/XMLHttpRequest/