<textarea><!--</textarea>--></textarea> should create a textarea with the contents "<!--</textarea>-->", and it does in firefox, ie, opera. in safari/webkit, it creates a textarea with "<!--"
According to the HTML 5 spec, Firefox/IE/Opera are correct; the textarea should contain "<!--</textarea>-->". http://www.whatwg.org/specs/web-apps/current-work/#cdata-rcdata-restrictions
Created attachment 21898 [details] Patch I wanted to learn more about the HTML parser, but this turned out to be super easy to fix.
Comment on attachment 21898 [details] Patch r=me
Fixed in r34787.