HTML and CSS Reference
In-Depth Information
SERVER-SENT EVENTS
The XMLHttpRequest object lets your web page ask the
web server a question and get an immediate answer. It's
a one-for-one exchange—once the web server provides
its response, the interaction is over. There's no way for
the web server to wait a few minutes and send another
message with an update.
However, there are some types of web pages that could
use a longer-term web server relationship. For example,
think of a stock quote on Google Finance
(
www.google.com/finance
)
. When you leave that page
open on your desktop, you'll see regular price updates
appear automatically. Another example is a news ticker
like the one at
www.bbc.co.uk/news
. Linger here, and
