<!doctype html> <html> <head> <title>XMLHttpRequest: setRequestHeader() before open()</title> <script src="/resources/testharness.js"></script> <script src="/resources/testharnessreport.js"></script> <link rel="help" href="https://xhr.spec.whatwg.org/#the-setrequestheader()-method" data-tested-assertations="following::ol/li[1]" /> </head> <body> <div id="log"></div> <script> test(function() { var client = new XMLHttpRequest() assert_throws_dom("InvalidStateError", function() { client.setRequestHeader("x-test", "test") }) }, 'setRequestHeader invoked before open()') </script> </body> </html>