constructor-submitter-coordinate.html

<!DOCTYPE html>
<meta charset='utf-8'>
<link rel='help' href='https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#constructing-the-form-data-set'>
<link ref='help' href='https://xhr.spec.whatwg.org/#dom-formdata'>
<script src='/resources/testharness.js'></script>
<script src='/resources/testharnessreport.js'></script>

<form>
  <input type=image src='/media/1x1-green.png'></button>
</form>

<script>
"use strict";

test(() => {
  const form = document.querySelector("form");
  const submitter = form.querySelector("input[type=image]");

  let formData;
  form.addEventListener("submit", e => {
    e.preventDefault();
    formData = new FormData(form, submitter);
  });

  const domRect = submitter.getBoundingClientRect();
  submitter.dispatchEvent(
    new MouseEvent("click", {
      clientX: Math.round(domRect.x) + 1,
      clientY: Math.round(domRect.y) + 2
    })
  );

  assert_equals(formData?.get("x"), "1");
  assert_equals(formData?.get("y"), "2");
}, "The constructed FormData object should contain correct entries for Image Button submitter's dispatched coordinate");
</script>

chromium/third_party/blink/web_tests/external/wpt/xhr/formdata/constructor-submitter-coordinate.html