"use strict"; async_test(t => { const xhr = new XMLHttpRequest(); xhr.open("POST", "resources/echo-content-type.py"); xhr.setRequestHeader("content-type", "application/json; charset=UTF-8"); xhr.onerror = t.unreached_func("Error occurred."); xhr.onload = t.step_func_done(() => { assert_equals(xhr.status, 200); assert_equals(xhr.responseText, "application/json; charset=UTF-8"); }); xhr.send("{ \"x\":\"a\"}"); });