gecko-dev/testing/web-platform/tests/domparsing/innerhtml-07.html

<!DOCTYPE html>
<title>innerHTML and string conversion</title>
<link rel="author" title="Ms2ger" href="mailto:ms2ger@gmail.com">
<link rel="help" href="https://w3c.github.io/DOM-Parsing/#extensions-to-the-element-interface">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="log"></div>
<script>
test(function() {
  var p = document.createElement("p");
  p.innerHTML = null;
  assert_equals(p.innerHTML, "");
  assert_equals(p.textContent, "");
}, "innerHTML and string conversion: null.")

test(function() {
  var p = document.createElement("p");
  p.innerHTML = undefined;
  assert_equals(p.innerHTML, "undefined");
  assert_equals(p.textContent, "undefined");
}, "innerHTML and string conversion: undefined.")

test(function() {
  var p = document.createElement("p");
  p.innerHTML = 42;
  assert_equals(p.innerHTML, "42");
  assert_equals(p.textContent, "42");
}, "innerHTML and string conversion: number.")

test(function() {
  var p = document.createElement("p");
  p.innerHTML = {
    toString: function() { return "pass"; },
    valueOf: function() { return "fail"; }
  };
  assert_equals(p.innerHTML, "pass");
  assert_equals(p.textContent, "pass");
}, "innerHTML and string conversion: toString.")

test(function() {
  var p = document.createElement("p");
  p.innerHTML = {
    toString: undefined,
    valueOf: function() { return "pass"; }
  };
  assert_equals(p.innerHTML, "pass");
  assert_equals(p.textContent, "pass");
}, "innerHTML and string conversion: valueOf.")
</script>