Here is an additional past discussion of this topic: https://lists.w3.org/Archives/Public/public-webapps/2014JanMar/0232.html
Sincerely, James Greene On Fri, Feb 6, 2015 at 9:54 AM, Florian Bösch <pya...@gmail.com> wrote: > I had an Android device, but now I have an iPhone. In addition to the >> popup problem, and the fake "X" on ads, the iPhone browsers (Safari, >> Chrome, Opera) will start to show a site, then they will lock up for 10-30 >> seconds before finally becoming responsive. > > > Via. Ask Slashdot: > http://ask.slashdot.org/story/15/02/04/1626232/ask-slashdot-gaining-control-of-my-mobile-browser > > Note: Starting with Gecko 30.0 (Firefox 30.0 / Thunderbird 30.0 / >> SeaMonkey 2.27), synchronous requests on the main thread have been >> deprecated due to the negative effects to the user experience. > > > > Via > https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests > > Heads up! The XMLHttpRequest2 spec was recently changed to prohibit >> sending a synchronous request whenxhr.responseType is set. The idea behind >> the change is to help mitigate further usage of synchronous xhrs wherever >> possible. > > > Via http://updates.html5rocks.com/2012/01/Getting-Rid-of-Synchronous-XHRs > > >