diff --git a/dom/events/Event-timestamp-high-resolution.html b/dom/events/Event-timestamp-high-resolution.html
new file mode 100644
index 00000000000000..15aa014cfb79d2
--- /dev/null
+++ b/dom/events/Event-timestamp-high-resolution.html
@@ -0,0 +1,16 @@
+<!DOCTYPE html>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script type="text/javascript">
+'use strict';
+for (let eventType of [MouseEvent, KeyboardEvent, WheelEvent, GamepadEvent, FocusEvent]) {
+    test(function() {
+        let before = performance.now();
+        let e = new eventType('test');
+        let after = performance.now();
+        assert_greater_than_equal(e.timeStamp, before, "Event timestamp should be greater than performance.now() timestamp taken before its creation");
+        assert_less_than_equal(e.timeStamp, after, "Event timestamp should be less than performance.now() timestamp taken after its creation");
+    }, `Constructed ${eventType.prototype.constructor.name} timestamp should be high resolution and have the same time origin as performance.now()`);
+}
+</script>
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diff --git a/dom/events/Event-timestamp-safe-resolution.html b/dom/events/Event-timestamp-safe-resolution.html
new file mode 100644
index 00000000000000..c19c7a0fb82490
--- /dev/null
+++ b/dom/events/Event-timestamp-safe-resolution.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script type="text/javascript">
+'use strict';
+
+test(function() {
+    let e1 = new MouseEvent('test1');
+    let e2 = new MouseEvent('test2');
+
+    while (e1.timeStamp == e2.timeStamp)
+        e2 = new MouseEvent('test2');
+
+    let expectedResolutionMilliseconds = 0.005;
+    let integerMultipleOfResolution = (e2.timeStamp - e1.timeStamp) / expectedResolutionMilliseconds;
+    let shouldBeNearZeroOrOne = integerMultipleOfResolution % 1;
+    assert_true(shouldBeNearZeroOrOne < 1e-10 || Math.abs(shouldBeNearZeroOrOne - 1) < 1e-10);
+}, 'Event timestamp should not have a resolution better that 5 microseconds');
+</script>
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