css/cssom-view/mouseEvent-offsetXY-svg.html

<!doctype html>
<title>MouseEvent.offsetX/Y returns coordinates relative to the root svg</title>
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<link rel="author" title="Mozilla" href="https://mozilla.org">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1684973">
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/1508">
<link rel="help" href="https://drafts.csswg.org/cssom-view/#dom-mouseevent-offsetx">
<script src=/resources/testharness.js></script>
<script src=/resources/testharnessreport.js></script>
<script src="/resources/testdriver.js"></script>
<script src="/resources/testdriver-vendor.js"></script>
<style>
  body { margin: 0 }
</style>
<svg width=100 height=100>
  <rect width=30 height=30 x=50 y=50 fill=green></rect>
</svg>
<script>
let t = async_test();
let rect = document.querySelector("rect");
rect.addEventListener("click", t.step_func_done(function(e) {
  assert_true(e.offsetX >= 50);
  assert_true(e.offsetY >= 50);
}))

test_driver.click(rect);
</script>