mozilla-release/testing/web-platform/tests/eventsource/format-mime-trailing-semicolon.htm

<!DOCTYPE html>
<html>
  <head>
    <title>EventSource: MIME type with trailing ;</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
  </head>
  <body>
    <div id="log"></div>
    <script>
      var test = async_test()
      test.step(function() {
        var source = new EventSource("resources/message.py?mime=text/event-stream%3B")
        source.onopen = function() {
          test.step(function() {
            assert_equals(source.readyState, source.OPEN)
            source.close()
          })
          test.done()
        }
        source.onerror = function() {
          test.step(function() {
            assert_unreached()
            source.close()
          })
          test.done()
        }
      })
    </script>
  </body>
</html>