XMLHttpRequest responseType = “json” giving error SYNTAX_ERR: DOM Exception 12

Question

I am having trouble setting the XHR responseType to \"json\". It works fine if I leave it an empty string xml.responseType = \"\"; but when I set it to \"json\

Answer 1

responseType property for XMLHttpRequest object is added in its new variant XMLHttpRequest Level 2 and which is included in HTML 5, i am not sure all browsers support this method so it could be possible that you are using a browser which doesn't implement that method

instead of using responseType you can use following code to get data in desired format

 var xml = new XMLHttpRequest();
 xml.open("GET", "test.php", true);

 xml.onreadystatechange = function() {
   if (xml.readyState != 4)  { return; }

   var serverResponse = JSON.parse(xml.responseText);
 };

 xml.send(null);

Answer 2

The JSON responseType is not implemented in the WebKit. http://groups.google.com/a/chromium.org/group/chromium-bugs/browse_thread/thread/8107e50e4207eb5a/a5d2c31247feae56?lnk=raot

Update 2016-01-03: As could be expected, WebKit has implemented this feature in the meantime.