XMLHttpRequest object dynamic nature

[M B HONG 20]

Hi all -

I am currently researching methods to push information onto client
browsers from the server. I have come to many dead ends, but have come
across one site in particular:
http://danga.com:8070/misc/jsdraw/xmlhttp.html
they seem to redraw the page without the use of polling the server.
Can anyone help me understand how this is done? Thanks in advance for
any help you can provide.

 

[David Dorward]

M B HONG 20 wrote:

I am currently researching methods to push information onto client
browsers from the server. I have come to many dead ends, but have come
across one site in particular:
http://danga.com:8070/misc/jsdraw/xmlhttp.html
they seem to redraw the page without the use of polling the server.

They poll the server. They just do so using XMLHttpRequest. I think (and I'm
no expert on XMLHttpRequest) that they issue a request as soon as the
previous request returns by sticking hr.send(null) in the function attached
to the onreadystatechange event.