diff --git a/html/semantics/scripting-1/the-script-element/moving-between-documents.html b/html/semantics/scripting-1/the-script-element/moving-between-documents.html
new file mode 100644
index 000000000000000..ed73036ab05e13c
--- /dev/null
+++ b/html/semantics/scripting-1/the-script-element/moving-between-documents.html
@@ -0,0 +1,138 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<title>Moving script elements between documents</title>
+<link rel="author" href="mailto:d@domenic.me" title="Domenic Denicola">
+<link rel="help" href="https://html.spec.whatwg.org/multipage/#execute-the-script-block">
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<!-- Background:
+
+- https://www.w3.org/Bugs/Public/show_bug.cgi?id=11323
+- https://github.com/whatwg/html/issues/2137
+- https://github.com/whatwg/html/issues/2469
+- https://github.com/whatwg/html/pull/2673
+
+-->
+
+<body>
+<script>
+"use strict";
+window.didExecute = false;
+
+async_test(t => {
+  t.add_cleanup(() => {
+    window.didExecute = false;
+  });
+
+  const iframe = document.createElement("iframe");
+  iframe.onload = t.step_func_done(() => {
+    iframe.contentWindow.didExecute = false;
+    iframe.contentDocument.write("<streaming-element>");
+    document.body.appendChild(iframe.contentDocument.querySelector("streaming-element"));
+    iframe.contentDocument.write(`<script id="s1">window.didExecute = true;<` + "/script>");
+    iframe.contentDocument.write("</streaming-element>");
+
+    const s = document.querySelector("#s1");
+    s.onload = t.unreached_func("onload");
+    s.onerror = t.unreached_func("onerror");
+
+    iframe.contentDocument.close();
+
+    assert_false(window.didExecute, "The script must not have executed in this window");
+    assert_equals(iframe.contentWindow.didExecute, undefined,
+      "The script must not have executed in the iframe window");
+  });
+
+  document.body.appendChild(iframe);
+}, "Moving to another document during parsing, inline script");
+
+async_test(t => {
+  t.add_cleanup(() => {
+    window.didExecute = false;
+  });
+
+  const iframe = document.createElement("iframe");
+  iframe.onload = t.step_func(() => {
+    iframe.contentWindow.didExecute = false;
+    iframe.contentDocument.write("<streaming-element>");
+    document.body.appendChild(iframe.contentDocument.querySelector("streaming-element"));
+    iframe.contentDocument.write(`<script id="s2" src="resources/flag-setter.js"><` + "/script>");
+    iframe.contentDocument.write("</streaming-element>");
+
+    const s = document.querySelector("#s2");
+    s.onload = t.unreached_func("onload");
+    s.onerror = t.unreached_func("onerror");
+
+    iframe.contentDocument.close();
+
+    t.step_timeout(() => {
+      assert_false(window.didExecute, "The script must not have executed in this window");
+      assert_equals(iframe.contentWindow.didExecute, undefined,
+        "The script must not have executed in the iframe window");
+      t.done();
+    }, 3000);
+  });
+
+  document.body.appendChild(iframe);
+}, "Moving to another document during parsing, external script");
+
+async_test(t => {
+  t.add_cleanup(() => {
+    window.didExecute = false;
+  });
+
+  const iframe = document.createElement("iframe");
+  iframe.onload = t.step_func(() => {
+    const s = document.createElement("script");
+    s.src = "resources/slow-flag-setter.py";
+    s.onload = t.unreached_func("onload");
+    s.onerror = t.unreached_func("onerror");
+
+    // Start the fetch
+    document.body.appendChild(s);
+
+    // Need to delay since the "prepare a script" algorithm also contains related checks; we want to
+    // test the "execute a script block" algorithm for when the fetch comes back.
+    t.step_timeout(() => {
+      iframe.contentDocument.body.appendChild(s);
+    }, 0);
+
+    t.step_timeout(() => {
+      assert_false(window.didExecute, "The script must not have executed in this window");
+      assert_equals(iframe.contentWindow.didExecute, undefined,
+        "The script must not have executed in the iframe window");
+      t.done();
+    }, 3000);
+  });
+
+  document.body.appendChild(iframe);
+}, "Moving to another Window's document during fetching");
+
+async_test(t => {
+  t.add_cleanup(() => {
+    window.didExecute = false;
+  });
+
+  const s = document.createElement("script");
+  s.src = "resources/slow-flag-setter.py";
+  s.onload = t.unreached_func("onload");
+  s.onerror = t.unreached_func("onerror");
+
+  // Start the fetch
+  document.body.appendChild(s);
+
+  // Need to delay since the "prepare a script" algorithm also contains related checks; we want to
+  // test the "execute a script block" algorithm for when the fetch comes back.
+  t.step_timeout(() => {
+    const doc2 = document.implementation.createHTMLDocument("title");
+    doc2.body.appendChild(s);
+  }, 0);
+
+  t.step_timeout(() => {
+      assert_false(window.didExecute, "The script must not have executed in this window");
+    t.done();
+  }, 3000);
+}, "Moving to a document where scripting is disabled during fetching");
+</script>
diff --git a/html/semantics/scripting-1/the-script-element/resources/flag-setter.js b/html/semantics/scripting-1/the-script-element/resources/flag-setter.js
new file mode 100644
index 000000000000000..3274e5bfeb26c62
--- /dev/null
+++ b/html/semantics/scripting-1/the-script-element/resources/flag-setter.js
@@ -0,0 +1,3 @@
+"use strict";
+
+window.didExecute = true;
diff --git a/html/semantics/scripting-1/the-script-element/resources/slow-flag-setter.py b/html/semantics/scripting-1/the-script-element/resources/slow-flag-setter.py
new file mode 100644
index 000000000000000..3ba3e892cb845eb
--- /dev/null
+++ b/html/semantics/scripting-1/the-script-element/resources/slow-flag-setter.py
@@ -0,0 +1,10 @@
+
+import time
+
+def main(request, response):
+  time.sleep(1)
+
+  headers = [("Content-Type", "text/javascript")]
+  body = "window.didExecute = true;"
+
+  return headers, body
