UIWebView in multithread ViewController

Question

I have a UIWebView in a viewcontroller, which has two methods as below. The question is if I pop out(tap back on navigation bar) this controller before the second thread is

Answer 1

I tried both solutions posted above, [operationQueue cancelAllOperations], and [[self retain] autorelease]. However, with quick clicking, there are still cases where the retain count falls to 0 and the class gets deallocated on the secondary thread. In order to avoid a crash, I put the following in my dealloc for now:

    if ([NSThread isMainThread]) {
        [super dealloc];
    }

which is an obvious leak, but seems to be the lesser of 2 evils.

Any additional insight from anyone encountering this problem is welcome.