Is it possible to abort a synchronous XmlHttpRequest?

Question

I have written a JavaScript function that asynchronously calls a web service using XmlHttpRequest. I have been asked to make this function finish its work before the page is

Answer 1

You can't:

http://www.hunlock.com/blogs/Snippets:_Synchronous_AJAX sais: "Synchronous AJAX (Really SJAX -- Synchronous Javascript and XML) is modal which means that javascript will stop processing your program until a result has been obtained from the server. While the request is processing, the browser is effectively frozen. The browser treats the call like an alert box or a prompt box only it doesn't wait for input from the user, but on input by the remote server"

Once the browser runs the sync request, it will wait until it will get a response.