diff --git a/html/semantics/interactive-elements/the-dialog-element/dialog-active-document.html b/html/semantics/interactive-elements/the-dialog-element/dialog-active-document.html
new file mode 100644
index 00000000000000..d6eea38fa8a399
--- /dev/null
+++ b/html/semantics/interactive-elements/the-dialog-element/dialog-active-document.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<link rel="author" href="mailto:masonf@chromium.org">
+<link rel=help href="https://github.com/whatwg/html/pull/10705">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+  test(() => {
+    const doc = document.implementation.createHTMLDocument();
+    const dialog = doc.createElement('dialog');
+    doc.body.appendChild(dialog);
+    assert_throws_dom('InvalidStateError',() => dialog.showModal());
+    assert_false(dialog.matches('[open]'));
+  },'showModal should throw when the document isn\'t active');
+</script>
diff --git a/html/semantics/interactive-elements/the-dialog-element/dialog-showModal.html b/html/semantics/interactive-elements/the-dialog-element/dialog-showModal.html
index 47612e759eaa49..652378e015b56d 100644
--- a/html/semantics/interactive-elements/the-dialog-element/dialog-showModal.html
+++ b/html/semantics/interactive-elements/the-dialog-element/dialog-showModal.html
@@ -181,8 +181,7 @@
     doc.body.appendChild(d11);
     this.add_cleanup(() => document.body.append(d11));
     assert_false(d11.open);
-    d11.showModal();
-    assert_true(d11.open);
-    this.add_cleanup(() => d11.close());
-  }, "Although the document is not attached to any pages, showModal() should execute as normal.");
+    assert_throws_dom("INVALID_STATE_ERR", () => d11.showModal());
+    assert_false(d11.open);
+  }, "When the document is not attached to any pages, showModal() should throw.");
 </script>
diff --git a/html/semantics/popovers/popover-active-document.html b/html/semantics/popovers/popover-active-document.html
new file mode 100644
index 00000000000000..6ad1142ed79c64
--- /dev/null
+++ b/html/semantics/popovers/popover-active-document.html
@@ -0,0 +1,17 @@
+<!DOCTYPE html>
+<meta charset="utf-8">
+<link rel="author" href="mailto:masonf@chromium.org">
+<link rel=help href="https://github.com/whatwg/html/pull/10705">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+  test(() => {
+    const doc = document.implementation.createHTMLDocument();
+    const popover = doc.createElement('div');
+    popover.setAttribute('popover','');
+    doc.body.appendChild(popover);
+    assert_throws_dom('InvalidStateError',() => popover.showPopover());
+    assert_false(popover.matches(':open'));
+  },'showPopover should throw when the document isn\'t active');
+</script>
