browser app limitation?

Has anyone looked into the issue of browsers limiting the number of
simultaneous network operations that apps running in browsers may perform?

For instance, I gather that different browsers put different limits on the
number of simultaneous downloads an app may perform. I presume (though am
not sure) that the notion generalizes to simply limiting the number of
network info requests, whether the request is to get an image or an html
page or whatever.

Anybody know of any good docs on this issue?

ja
http://vispo.com