137865 2014-10-19 12:19:25 -0700 XMLHttpRequest using wrong default content-type, forcing CORS preflight 2014-10-21 09:50:28 -0700 1 1 1 Unclassified WebKit New Bugs 528+ (Nightly build) Mac (Intel) Other RESOLVED DUPLICATE 99973 P2 Normal --- 1 chrisjshull webkit-unassigned ap youennf oldest_to_newest 1042694 0 chrisjshull 2014-10-19 12:19:25 -0700 Per http://www.w3.org/TR/XMLHttpRequest2/#the-send-method When sending a string: Let mime type be "text/plain;charset=UTF-8". Now try this with an HTTP proxy/monitor and Safari 8.0: var xhr = new XMLHttpRequest(); var url = "http://www.corsproxy.com/en.wikipedia.org/wiki/Http?" + Date.now(); xhr.open("POST", url, true); xhr.send("test"); Observed: An OPTIONS preflight. Because the Content-Type in the POST request has been set to application/xml. Expected: No OPTIONS preflight. Content-Type in the POST request to be text/plain;charset=UTF-8. 1042695 1 chrisjshull 2014-10-19 12:23:54 -0700 For note, Chrome v38 handles this correctly, as does Forefox v33. 1043092 2 ap 2014-10-20 20:59:11 -0700 I think that "text/plain;charset=UTF-8" would also cause preflight, as the implementation stands now. *** This bug has been marked as a duplicate of bug 99973 *** 1043144 3 youennf 2014-10-21 01:35:11 -0700 (In reply to comment #2) > I think that "text/plain;charset=UTF-8" would also cause preflight, as the > implementation stands now. The request should already be considered as simple by the latest webkit revision. I will double check this and report. 1043205 4 ap 2014-10-21 09:50:28 -0700 Yes, looks like I was wrong, it doesn't cause a preflight any more.