See https://jsfiddle.net/mjba21mk/5/ <form name="f"> <input type="radio" name="r" value="value1" /> <input type="radio" name="r" value="value2" checked /> </form> document.f.r.value is undefined - as document.f.r is a NodeList document.f.r.value should be “value2” - as document.f.r should be a RadioNodeList Relevant spec https://w3c.github.io/html/single-page.html#the-htmlformcontrolscollection-interface Works in latest Chrome, Firefox; will be fixed soon in Edge This bug might be covered by https://bugs.webkit.org/show_bug.cgi?id=150957 Seen on https://www.washingtonpost.com/news/the-fix/wp/2015/10/06/hey-lets-all-make-our-own-donald-trump-hats/ User can’t create a white-and-gold hat in the MAKE A HAT GREAT AGAIN section
Did not mean to close this yet.
Actually, based on the test case, the issue is with HTMLFormElement's named property getter.
Created attachment 272732 [details] Patch
Comment on attachment 272732 [details] Patch Clearing flags on attachment: 272732 Committed r197497: <http://trac.webkit.org/changeset/197497>
All reviewed patches have been landed. Closing bug.