layer or something in middle of browser?

[TheIceman5]

i have been noticing lately that more sites are having this little popup thing that looks like a layer of some sort when a page is loading or you are uploading something. the attached picture shows what i mean, if you look in the centre it has a window or layer or something that says the page is loading.
how do you create such a thing? what is it called?

[thorpe]

javascript mixed with some ajax i should imagine.

[TheIceman5]

whats ajax?

[thorpe]

ajax

[Rodney_H_]

I have used javascript before and reviewed these scripts to get ideas:

http://rainbow.arch.scriptmania.com/scripts/preload_wait.html

and

http://javascript.internet.com/css/pre-loading-message.html

You can make something very professional looking with a good animated "loading.gif" that is small in file size...

Something along the lines of this (but make your own...)

[TheIceman5]

yeah thats the sort of things im looking for,thanks.