<!DOCTYPE html>
<meta charset=utf-8>
<title>Document.getElementById</title>
<link rel="author" title="Tetsuharu OHZEKI" href="mailto:saneyuki.snyk@gmail.com">
<link rel=help href="https://dom.spec.whatwg.org/#dom-document-getelementbyid">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<body>
<div id="log"></div>
<!-- test 0 -->
<div id=""></div>
<!-- test 1 -->
<div id="test1"></div>
<!-- test 5 -->
<div id="test5" data-name="1st">
<p id="test5" data-name="2nd">P</p>
<input id="test5" type="submit" value="Submit" data-name="3rd">
</div>
<!-- test 15 -->
<div id="outer">
<div id="middle">
<div id="inner"></div>
</div>
</div>
<script>
var gBody = document.getElementsByTagName("body")[0];
test(function() {
assert_equals(document.getElementById(""), null);
}, "Calling document.getElementById with an empty string argument.");
test(function() {
var element = document.createElement("div");
element.setAttribute("id", "null");
document.body.appendChild(element);
this.add_cleanup(function() { document.body.removeChild(element) });
assert_equals(document.getElementById(null), element);
}, "Calling document.getElementById with a null argument.");
test(function() {
var element = document.createElement("div");
element.setAttribute("id", "undefined");
document.body.appendChild(element);
this.add_cleanup(function() { document.body.removeChild(element) });
assert_equals(document.getElementById(undefined), element);
}, "Calling document.getElementById with an undefined argument.");
test(function() {
var bar = document.getElementById("test1");
assert_not_equals(bar, null, "should not be null");
assert_equals(bar.tagName, "DIV", "should have expected tag name.");
assert_true(bar instanceof HTMLDivElement, "should be a valid Element instance");
}, "on static page");
test(function() {
var TEST_ID = "test2";
var test = document.createElement("div");
test.setAttribute("id", TEST_ID);
gBody.appendChild(test);
// test: appended element
var result = document.getElementById(TEST_ID);
assert_not_equals(result, null, "should not be null.");
assert_equals(result.tagName, "DIV", "should have appended element's tag name");
assert_true(result instanceof HTMLDivElement, "should be a valid Element instance");
// test: removed element
gBody.removeChild(test);
var removed = document.getElementById(TEST_ID);
// `document.getElementById()` returns `null` if there is none.
// https://dom.spec.whatwg.org/#dom-nonelementparentnode-getelementbyid
assert_equals(removed, null, "should not get removed element.");
}, "Document.getElementById with a script-inserted element");
test(function() {
// setup fixtures.
var TEST_ID = "test3";
var test = document.createElement("div");
test.setAttribute("id", TEST_ID);
gBody.appendChild(test);
// update id
var UPDATED_ID = "test3-updated";
test.setAttribute("id", UPDATED_ID);
var e = document.getElementById(UPDATED_ID);
assert_equals(e, test, "should get the element with id.");
var old = document.getElementById(TEST_ID);
assert_equals(old, null, "shouldn't get the element by the old id.");
// remove id.
test.removeAttribute("id");
var e2 = document.getElementById(UPDATED_ID);
assert_equals(e2, null, "should return null when the passed id is none in document.");
}, "update `id` attribute via setAttribute/removeAttribute");
test(function() {
var TEST_ID = "test4-should-not-exist";
var e = document.createElement('div');
e.setAttribute("id", TEST_ID);
assert_equals(document.getElementById(TEST_ID), null, "should be null");
document.body.appendChild(e);
assert_equals(document.getElementById(TEST_ID), e, "should be the appended element");
}, "Ensure that the id attribute only affects elements present in a document");
test(function() {
// the method should return the 1st element.
var TEST_ID = "test5";
var target = document.getElementById(TEST_ID);
assert_not_equals(target, null, "should not be null");
assert_equals(target.getAttribute("data-name"), "1st", "should return the 1st");
// even if after the new element was appended.
var element4 = document.createElement("div");
element4.setAttribute("id", TEST_ID);
element4.setAttribute("data-name", "4th");
gBody.appendChild(element4);
var target2 = document.getElementById(TEST_ID);
assert_not_equals(target2, null, "should not be null");
assert_equals(target2.getAttribute("data-name"), "1st", "should be the 1st");
// should return the next element after removed the subtree including the 1st element.
target2.parentNode.removeChild(target2);
var target3 = document.getElementById(TEST_ID);
assert_not_equals(target3, null, "should not be null");
assert_equals(target3.getAttribute("data-name"), "4th", "should be the 4th");
}, "in tree order, within the context object's tree");
test(function() {
var TEST_ID = "test6";
var s = document.createElement("div");
s.setAttribute("id", TEST_ID);
// append to Element, not Document.
document.createElement("div").appendChild(s);
assert_equals(document.getElementById(TEST_ID), null, "should be null");
}, "Modern browsers optimize this method with using internal id cache. " +
"This test checks that their optimization should effect only append to `Document`, not append to `Node`.");
test(function() {
var TEST_ID = "test7"
var element = document.createElement("div");
element.setAttribute("id", TEST_ID);
gBody.appendChild(element);
var target = document.getElementById(TEST_ID);
assert_equals(target, element, "should return the element before changing the value");
element.attributes[0].value = TEST_ID + "-updated";
var target2 = document.getElementById(TEST_ID);
assert_equals(target2, null, "should return null after updated id via Attr.value");
var target3 = document.getElementById(TEST_ID + "-updated");
assert_equals(target3, element, "should be equal to the updated element.");
}, "changing attribute's value via `Attr` gotten from `Element.attribute`.");
test(function() {
var TEST_ID = "test8";
// setup fixture
var element = document.createElement("div");
element.setAttribute("id", TEST_ID + "-fixture");
gBody.appendChild(element);
// add id-ed element with using innerHTML
element.innerHTML = "<div id='"+ TEST_ID +"'></div>";
var test = document.getElementById(TEST_ID);
assert_equals(test, element.firstChild, "should not be null");
assert_equals(test.tagName, "DIV", "should have expected tag name.");
assert_true(test instanceof HTMLDivElement, "should be a valid Element instance");
}, "add id attribute via innerHTML");
test(function() {
var TEST_ID = "test9";
// add fixture
var fixture = document.createElement("div");
fixture.setAttribute("id", TEST_ID + "-fixture");
gBody.appendChild(fixture);
var element = document.createElement("div");
element.setAttribute("id", TEST_ID);
fixture.appendChild(element);
// check 'getElementById' should get the 'element'
assert_equals(document.getElementById(TEST_ID), element, "should not be null");
// remove id-ed element with using innerHTML (clear 'element')
fixture.innerHTML = "";
var test = document.getElementById(TEST_ID);
assert_equals(test, null, "should be null.");
}, "remove id attribute via innerHTML");
test(function() {
var TEST_ID = "test10";
// setup fixture
var element = document.createElement("div");
element.setAttribute("id", TEST_ID + "-fixture");
gBody.appendChild(element);
// add id-ed element with using outerHTML
element.outerHTML = "<div id='"+ TEST_ID +"'></div>";
var test = document.getElementById(TEST_ID);
assert_not_equals(test, null, "should not be null");
assert_equals(test.tagName, "DIV", "should have expected tag name.");
assert_true(test instanceof HTMLDivElement,"should be a valid Element instance");
}, "add id attribute via outerHTML");
test(function() {
var TEST_ID = "test11";
var element = document.createElement("div");
element.setAttribute("id", TEST_ID);
gBody.appendChild(element);
var test = document.getElementById(TEST_ID);
assert_equals(test, element, "should be equal to the appended element.");
// remove id-ed element with using outerHTML
element.outerHTML = "<div></div>";
var test = document.getElementById(TEST_ID);
assert_equals(test, null, "should be null.");
}, "remove id attribute via outerHTML");
test(function() {
// setup fixtures.
var TEST_ID = "test12";
var test = document.createElement("div");
test.id = TEST_ID;
gBody.appendChild(test);
// update id
var UPDATED_ID = TEST_ID + "-updated";
test.id = UPDATED_ID;
var e = document.getElementById(UPDATED_ID);
assert_equals(e, test, "should get the element with id.");
var old = document.getElementById(TEST_ID);
assert_equals(old, null, "shouldn't get the element by the old id.");
// remove id.
test.id = "";
var e2 = document.getElementById(UPDATED_ID);
assert_equals(e2, null, "should return null when the passed id is none in document.");
}, "update `id` attribute via element.id");
test(function() {
var TEST_ID = "test13";
var create_same_id_element = function (order) {
var element = document.createElement("div");
element.setAttribute("id", TEST_ID);
element.setAttribute("data-order", order);// for debug
return element;
};
// create fixture
var container = document.createElement("div");
container.setAttribute("id", TEST_ID + "-fixture");
gBody.appendChild(container);
var element1 = create_same_id_element("1");
var element2 = create_same_id_element("2");
var element3 = create_same_id_element("3");
var element4 = create_same_id_element("4");
// append element: 2 -> 4 -> 3 -> 1
container.appendChild(element2);
container.appendChild(element4);
container.insertBefore(element3, element4);
container.insertBefore(element1, element2);
var test = document.getElementById(TEST_ID);
assert_equals(test, element1, "should return 1st element");
container.removeChild(element1);
test = document.getElementById(TEST_ID);
assert_equals(test, element2, "should return 2nd element");
container.removeChild(element2);
test = document.getElementById(TEST_ID);
assert_equals(test, element3, "should return 3rd element");
container.removeChild(element3);
test = document.getElementById(TEST_ID);
assert_equals(test, element4, "should return 4th element");
container.removeChild(element4);
}, "where insertion order and tree order don't match");
test(function() {
var TEST_ID = "test14";
var a = document.createElement("a");
var b = document.createElement("b");
a.appendChild(b);
b.id = TEST_ID;
assert_equals(document.getElementById(TEST_ID), null);
gBody.appendChild(a);
assert_equals(document.getElementById(TEST_ID), b);
}, "Inserting an id by inserting its parent node");
test(function () {
var TEST_ID = "test15"
var outer = document.getElementById("outer");
var middle = document.getElementById("middle");
var inner = document.getElementById("inner");
outer.removeChild(middle);
var new_el = document.createElement("h1");
new_el.id = "heading";
inner.appendChild(new_el);
// the new element is not part of the document since
// "middle" element was removed previously
assert_equals(document.getElementById("heading"), null);
}, "Document.getElementById must not return nodes not present in document");
// TODO:
// id attribute in a namespace
// TODO:
// SVG + MathML elements with id attributes
</script>
</body>
</html>