I'm not really disputing the time anything will take, rather that "A+ doesn't require that you use the browser's asynchronous scheduling mechanism" – it very mu

I'm not really disputing the time anything will take, rather that "A+ doesn't require that you use the browser's asynchronous scheduling mechanism" – it very much does, even though that scheduling mechanism might be to occasionally flush your own managed event queue instead of handing every callback to the browser.