It takes a bit of code but if you know the length of the response you're expecting then you can use XHR's "progress" event. Just be aware that the event will ha

It takes a bit of code but if you know the length of the response you're expecting then you can use XHR's "progress" event. Just be aware that the event will happen frequently and contain all the data so far, to avoid inefficient parsing and substring related memory leaks. I think his problem might be more about using JS in WordPress though.