While, in this case, it was for science, presumably, the inhumane and especially cruel flaying of millions of live dogs, cats and other animals happens every year in parts of China and around the world. Not necessarily for the meat, but for a few bucks to be made off the sale of the skin.
OMG I laid the groundwork for the Falling Fruit mobile app, but I had to step aside and it was all so long ago! It has come along leaps and bounds since then.
The browser app has always been way ahead and the programmers behind the whole idea are super competent.
Sending your password in plain text in email doesn't mean it's stored in plain text; it could be copied from memory into the email before being discarded at the end of execution of the initial request.
I'm not sure why you were downvoted but it's possible that your question was too basic from the point of view of a web developer.
To answer your question: one reason is that the developer needs to express how elements on a page place themselves not just on the screen but with respect to other elements as well. As you can guess, calculating this "layout" will occur pretty often, and if you have only one thread running all your code, then your logic and communication with the server can interfere with the rendering of the UI - thus making the response choppy.
On native apps, though some of them have borrowed web-type expressions of placement or layout, the entire calculation runs on a dedicated thread. Not on the same thread that also needs to respond to touch / slide / drag events!
Daniel King's daily reports on several elite tournaments over the past few years are excellent. For anyone interested in chess, I highly recommending watching his archived videos on youtube.
