Fix issues on asp.net website

i have created a website which uses ajax calls to retrieve data from a few sites and populates div! The issue is while those calls are made which use HTTPWEBREQUEST ... The pages is like stuck it is responsive but no other button on the page seems to respond to events. It's like i press a button to navigate to another page but it wont until those calls are done! 2 things to do! 1- when i navigate i want it to abort all ajax calls, and navigate to the desired page 2- During those calls i sometime run another ajax call which creates something on the page which also wait until all above are done. Let me know if something is not clear , and only experienced asp.net developers. Price will be good if you handle it professionally and deliver good expected result ONLY !