third_party/web_platform_tests/XMLHttpRequest/send-response-upload-event-loadstart.htm - cobalt - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
     <link rel="help" href="https://xhr.spec.whatwg.org/#handler-xhr-onloadstart" data-tested-assertations="../.." />
     <link rel="help" href="https://xhr.spec.whatwg.org/#event-xhr-loadstart" data-tested-assertations="../.." />
     <link rel="help" href="https://xhr.spec.whatwg.org/#the-send()-method" data-tested-assertations="following::ol[1]/li[8] following-sibling::ol/li[9]/ol/li[3]" />

     <script src="/resources/testharness.js"></script>
     <script src="/resources/testharnessreport.js"></script>
     <title>XMLHttpRequest: The send() method: Fire a progress event named loadstart on the XMLHttpRequestUpload (synchronous flag is unset)</title>
 </head>

 <body>
     <div id="log"></div>

     <script type="text/javascript">
         var test = async_test();

         test.step(function()
         {
             var xhr = new XMLHttpRequest();

             xhr.upload.onloadstart = function(e)
             {
                 test.step(function()
                 {
                     assert_true(e instanceof ProgressEvent);
                     assert_equals(e.type, "loadstart");
                     assert_equals(e.target, xhr.upload);
                     test.done();
                 });
             };

             xhr.open("POST", "./resources/content.py", true);
             xhr.send("Test Message");
         });
     </script>
 </body>
 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<link rel="help" href="https://xhr.spec.whatwg.org/#handler-xhr-onloadstart" data-tested-assertations="../.." />
	<link rel="help" href="https://xhr.spec.whatwg.org/#event-xhr-loadstart" data-tested-assertations="../.." />
	<link rel="help" href="https://xhr.spec.whatwg.org/#the-send()-method" data-tested-assertations="following::ol[1]/li[8] following-sibling::ol/li[9]/ol/li[3]" />

	<script src="/resources/testharness.js"></script>
	<script src="/resources/testharnessreport.js"></script>
	<title>XMLHttpRequest: The send() method: Fire a progress event named loadstart on the XMLHttpRequestUpload (synchronous flag is unset)</title>
	</head>

	<body>
	<div id="log"></div>

	<script type="text/javascript">
	var test = async_test();

	test.step(function()
	{
	var xhr = new XMLHttpRequest();

	xhr.upload.onloadstart = function(e)
	{
	test.step(function()
	{
	assert_true(e instanceof ProgressEvent);
	assert_equals(e.type, "loadstart");
	assert_equals(e.target, xhr.upload);
	test.done();
	});
	};

	xhr.open("POST", "./resources/content.py", true);
	xhr.send("Test Message");
	});
	</script>
	</body>
	</html>