Question

Say I wanted to write a local web server that listened on a random port.

Now I want to write HTML that works in most browsers that can do AJAX calls to it.

Is there any fundamental limitation here?

EDIT: I’ve confused people – probably because this is almost the first time I’ve ever posted with the javascript tag and I don’t have a feel for how to ask questions.

I recently became aware of node.js – which I didn’t learn more than it makes writing stand alone web servers easy to implement.

Then I had the vision of a site sort of like this one (any programming board really) but where code samples could execute on end users local machine. I don’t like browser plugins at all though, so I started trying to think of a way to make it happen with minimal knowledge between the web/browser part and the local machine’s service (there has to be interaction – i just wanted to think of the minimal amount).

And that is just an example – really I write intranet business apps for a living (in which case defining well known ports is easier so I don’t need an answer to this question for that purpose..)

Answer 1

The same origin policy will prevent you from accessing other ports (at least in most browsers), but you I guess you could send JSONP requests to every port on localhost, and then catch the port that gives a valid response.

…If you really wanted to, that is. There is a lot of valid ports, so it could take some time.