Is synchronous XMLHttpRequest supported in Internet Explorer 10 and 11?

Question

I am having no luck trying to find an authoritative answer to this question, prompted by the claim at caniuse.com that IE 10 and 11 have dropped support for synchronous requests. See the Known Issues tab on this page:

http://www.caniuse.com/#search=xmlhttprequest

The only reference to any problems with synchronous XMLHttpRequest in IE 11 that I could find are two invalid bug reports:

https://connect.microsoft.com/IE/feedback/details/810738/ie-11-synchronous-xmlhttprequest-fails https://connect.microsoft.com/IE/feedback/details/801404/ie-11-still-does-not-support-xmlhttprequest-async-false

Could someone confirm that synchronous is supported in these versions? Up until today I treated caniuse.com as authoritative, now I'm not so sure. I'll have to look into how they obtain their data.

Answer 1

By a happy coincidence I founda link on the jQuery Browser Support page to Virtual Machines offered by Microsoft for testing of IE 10 and 11. I downloaded the IE11/Win7 file, and used it to confirm that synchronous XMLHttpRequest works just fine in this browser. I'll notify caniuse.com, so they can correct their mistake. I will invite them to comment here as to how that mistake could happen - it undermines trust in their platform.