.htc files were a performance nightmare. They were (mis)used for pre IE8 polyfills - often delivered by ad-networks - and of course downloaded and executed in a

.htc files were a performance nightmare. They were (mis)used for pre IE8 polyfills - often delivered by ad-networks - and of course downloaded and executed in a synchronous blocking way. .htc maybe were a sane idea, but horribly executed.