diff --git a/docs/patterns/jquery.rst b/docs/patterns/jquery.rst
index 24569a53..8297bd44 100644
--- a/docs/patterns/jquery.rst
+++ b/docs/patterns/jquery.rst
@@ -162,5 +162,6 @@ explanation of the little bit of code above:
    argument.  Note that we can use the `$SCRIPT_ROOT` variable here that
    we set earlier.
 
-If you don't get the whole picture, download the :gh:`sourcecode
-for this example <examples/jqueryexample>`.
+Check out the :gh:`example source <examples/javascript>` for a full
+application demonstrating the jQuery on this page, as well as the same
+thing using ``XMLHttpRequest`` and ``fetch``.
diff --git a/docs/testing.rst b/docs/testing.rst
index bfbc1d91..82e10328 100644
--- a/docs/testing.rst
+++ b/docs/testing.rst
@@ -209,12 +209,6 @@ Running that should now give us three passing tests::
 
     ============= 3 passed in 0.23 seconds ==============
 
-For more complex tests with headers and status codes, check out the
-`MiniTwit Example`_ from the sources which contains a larger test
-suite.
-
-.. _MiniTwit Example:
-   https://github.com/pallets/flask/tree/master/examples/minitwit/
 
 Other Testing Tricks
 --------------------
diff --git a/examples/javascript/.gitignore b/examples/javascript/.gitignore
new file mode 100644
index 00000000..85a35845
--- /dev/null
+++ b/examples/javascript/.gitignore
@@ -0,0 +1,14 @@
+venv/
+*.pyc
+__pycache__/
+instance/
+.cache/
+.pytest_cache/
+.coverage
+htmlcov/
+dist/
+build/
+*.egg-info/
+.idea/
+*.swp
+*~
diff --git a/examples/javascript/LICENSE b/examples/javascript/LICENSE
new file mode 100644
index 00000000..8f9252f4
--- /dev/null
+++ b/examples/javascript/LICENSE
@@ -0,0 +1,31 @@
+Copyright © 2010 by the Pallets team.
+
+Some rights reserved.
+
+Redistribution and use in source and binary forms of the software as
+well as documentation, with or without modification, are permitted
+provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice,
+  this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in the
+  documentation and/or other materials provided with the distribution.
+
+* Neither the name of the copyright holder nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE AND DOCUMENTATION IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
+BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+THIS SOFTWARE AND DOCUMENTATION, EVEN IF ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGE.
diff --git a/examples/javascript/MANIFEST.in b/examples/javascript/MANIFEST.in
new file mode 100644
index 00000000..0ba3d5b8
--- /dev/null
+++ b/examples/javascript/MANIFEST.in
@@ -0,0 +1,4 @@
+include LICENSE
+graft js_example/templates
+graft tests
+global-exclude *.pyc
diff --git a/examples/javascript/README.rst b/examples/javascript/README.rst
new file mode 100644
index 00000000..fc074284
--- /dev/null
+++ b/examples/javascript/README.rst
@@ -0,0 +1,49 @@
+JavaScript Ajax Example
+=======================
+
+Demonstrates how to post form data and process a JSON response using
+JavaScript. This allows making requests without navigating away from the
+page. Demonstrates using |XMLHttpRequest|_, |fetch|_, and
+|jQuery.ajax|_. See the `Flask docs`_ about jQuery and Ajax.
+
+.. |XMLHttpRequest| replace:: ``XMLHttpRequest``
+.. _XMLHttpRequest: https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest
+
+.. |fetch| replace:: ``fetch``
+.. _fetch: https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch
+
+.. |jQuery.ajax| replace:: ``jQuery.ajax``
+.. _jQuery.ajax: https://api.jquery.com/jQuery.ajax/
+
+.. _Flask docs: http://flask.pocoo.org/docs/patterns/jquery/
+
+
+Install
+-------
+
+::
+
+    python3 -m venv venv
+    . venv/bin/activate
+    pip install -e .
+
+
+Run
+---
+
+::
+
+    export FLASK_APP=js_example
+    flask run
+
+Open http://127.0.0.1:5000 in a browser.
+
+
+Test
+----
+
+::
+
+    pip install -e '.[test]'
+    coverage run -m pytest
+    coverage report
diff --git a/examples/javascript/js_example/__init__.py b/examples/javascript/js_example/__init__.py
new file mode 100644
index 00000000..d90fc4d4
--- /dev/null
+++ b/examples/javascript/js_example/__init__.py
@@ -0,0 +1,5 @@
+from flask import Flask
+
+app = Flask(__name__)
+
+from js_example import views
diff --git a/examples/javascript/js_example/templates/base.html b/examples/javascript/js_example/templates/base.html
new file mode 100644
index 00000000..a4b4480e
--- /dev/null
+++ b/examples/javascript/js_example/templates/base.html
@@ -0,0 +1,33 @@
+<!doctype html>
+<title>JavaScript Example</title>
+<link rel="stylesheet" href="https://unpkg.com/sakura.css@1.0.0/css/normalize.css">
+<link rel="stylesheet" href="https://unpkg.com/sakura.css@1.0.0/css/sakura-earthly.css">
+<style>
+  ul { margin: 0; padding: 0; display: flex; list-style-type: none; }
+  li > * { padding: 1em; }
+  li.active > a { color: #5e5e5e; border-bottom: 2px solid #4a4a4a; }
+  form { display: flex; }
+  label > input { width: 3em; }
+  form > * { padding-right: 1em; }
+  #result { font-weight: bold; }
+</style>
+<ul>
+  <li><span>Type:</span>
+  <li class="{% if js == 'plain' %}active{% endif %}">
+    <a href="{{ url_for('index', js='plain') }}">Plain</a>
+  <li class="{% if js == 'fetch' %}active{% endif %}">
+    <a href="{{ url_for('index', js='fetch') }}">Fetch</a>
+  <li class="{% if js == 'jquery' %}active{% endif %}">
+    <a href="{{ url_for('index', js='jquery') }}">jQuery</a>
+</ul>
+<hr>
+<p>{% block intro %}{% endblock %}</p>
+<hr>
+<form>
+  <label>a <input name="a"></label>
+  <span>+</span>
+  <label>b <input name="b"></label>
+  <input type="submit" value="Calculate">
+</form>
+<span>= <span id="result"></span></span>
+{% block script %}{% endblock %}
diff --git a/examples/javascript/js_example/templates/fetch.html b/examples/javascript/js_example/templates/fetch.html
new file mode 100644
index 00000000..4d5fcc56
--- /dev/null
+++ b/examples/javascript/js_example/templates/fetch.html
@@ -0,0 +1,35 @@
+{% extends 'base.html' %}
+
+{% block intro %}
+  <a href="https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/fetch"><code>fetch</code></a>
+  is the <em>new</em> plain JavaScript way to make requests. It's
+  supported in all modern browsers except IE, which requires a
+  <a href="https://github.com/github/fetch">polyfill</a>.
+{% endblock %}
+
+{% block script %}
+  <script src="https://unpkg.com/promise-polyfill@7.1.2/dist/polyfill.min.js"></script>
+  <script src="https://unpkg.com/whatwg-fetch@2.0.4/fetch.js"></script>
+  <script>
+    function addSubmit(ev) {
+      ev.preventDefault();
+      fetch('{{ url_for('add') }}', {
+        method: 'POST',
+        body: new FormData(this)
+      })
+        .then(parseJSON)
+        .then(addShow);
+    }
+
+    function parseJSON(response) {
+      return response.json();
+    }
+
+    function addShow(data) {
+      var span = document.getElementById('result');
+      span.innerText = data.result;
+    }
+
+    document.forms[0].addEventListener('submit', addSubmit);
+  </script>
+{% endblock %}
diff --git a/examples/javascript/js_example/templates/jquery.html b/examples/javascript/js_example/templates/jquery.html
new file mode 100644
index 00000000..17bafd4d
--- /dev/null
+++ b/examples/javascript/js_example/templates/jquery.html
@@ -0,0 +1,27 @@
+{% extends 'base.html' %}
+
+{% block intro %}
+  <a href="https://jquery.com/">jQuery</a> is a popular library that
+  adds cross browser APIs for common tasks. However, it requires loading
+  an extra library.
+{% endblock %}
+
+{% block script %}
+  <script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>
+  <script>
+    function addSubmit(ev) {
+      ev.preventDefault();
+      $.ajax({
+        method: 'POST',
+        url: '{{ url_for('add') }}',
+        data: $(this).serialize()
+      }).done(addShow);
+    }
+
+    function addShow(data) {
+      $('#result').text(data.result);
+    }
+
+    $('form:first').on('submit', addSubmit);
+  </script>
+{% endblock %}
diff --git a/examples/javascript/js_example/templates/plain.html b/examples/javascript/js_example/templates/plain.html
new file mode 100644
index 00000000..98e81e53
--- /dev/null
+++ b/examples/javascript/js_example/templates/plain.html
@@ -0,0 +1,27 @@
+{% extends 'base.html' %}
+
+{% block intro %}
+  <a href="https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest"><code>XMLHttpRequest</code></a>
+  is the plain JavaScript way to make requests. It's natively supported
+  by all browsers.
+{% endblock %}
+
+{% block script %}
+  <script>
+    function addSubmit(ev) {
+      ev.preventDefault();
+      var request = new XMLHttpRequest();
+      request.addEventListener('load', addShow);
+      request.open('POST', '{{ url_for('add') }}');
+      request.send(new FormData(this));
+    }
+
+    function addShow() {
+      var data = JSON.parse(this.responseText);
+      var span = document.getElementById('result');
+      span.innerText = data.result;
+    }
+
+    document.forms[0].addEventListener('submit', addSubmit);
+  </script>
+{% endblock %}
diff --git a/examples/javascript/js_example/views.py b/examples/javascript/js_example/views.py
new file mode 100644
index 00000000..c898e6de
--- /dev/null
+++ b/examples/javascript/js_example/views.py
@@ -0,0 +1,16 @@
+from flask import jsonify, render_template, request
+
+from js_example import app
+
+
+@app.route('/', defaults={'js': 'plain'})
+@app.route('/<any(plain, jquery, fetch):js>')
+def index(js):
+    return render_template('{0}.html'.format(js), js=js)
+
+
+@app.route('/add', methods=['POST'])
+def add():
+    a = request.form.get('a', 0, type=float)
+    b = request.form.get('b', 0, type=float)
+    return jsonify(result=a + b)
diff --git a/examples/javascript/setup.cfg b/examples/javascript/setup.cfg
new file mode 100644
index 00000000..a14fa80e
--- /dev/null
+++ b/examples/javascript/setup.cfg
@@ -0,0 +1,13 @@
+[metadata]
+license_file = LICENSE
+
+[bdist_wheel]
+universal = True
+
+[tool:pytest]
+testpaths = tests
+
+[coverage:run]
+branch = True
+source =
+    js_example
diff --git a/examples/javascript/setup.py b/examples/javascript/setup.py
new file mode 100644
index 00000000..c699e8f1
--- /dev/null
+++ b/examples/javascript/setup.py
@@ -0,0 +1,30 @@
+import io
+
+from setuptools import find_packages, setup
+
+with io.open('README.rst', 'rt', encoding='utf8') as f:
+    readme = f.read()
+
+setup(
+    name='js_example',
+    version='1.0.0',
+    url='http://flask.pocoo.org/docs/patterns/jquery/',
+    license='BSD',
+    maintainer='Pallets team',
+    maintainer_email='contact@palletsprojects.com',
+    description='Demonstrates making Ajax requests to Flask.',
+    long_description=readme,
+    packages=find_packages(),
+    include_package_data=True,
+    zip_safe=False,
+    install_requires=[
+        'flask',
+    ],
+    extras_require={
+        'test': [
+            'pytest',
+            'coverage',
+            'blinker',
+        ],
+    },
+)
diff --git a/examples/javascript/tests/conftest.py b/examples/javascript/tests/conftest.py
new file mode 100644
index 00000000..ea81ba59
--- /dev/null
+++ b/examples/javascript/tests/conftest.py
@@ -0,0 +1,15 @@
+import pytest
+
+from js_example import app
+
+
+@pytest.fixture(name='app')
+def fixture_app():
+    app.testing = True
+    yield app
+    app.testing = False
+
+
+@pytest.fixture
+def client(app):
+    return app.test_client()
diff --git a/examples/javascript/tests/test_js_example.py b/examples/javascript/tests/test_js_example.py
new file mode 100644
index 00000000..f1bcf96d
--- /dev/null
+++ b/examples/javascript/tests/test_js_example.py
@@ -0,0 +1,28 @@
+import pytest
+
+from flask import template_rendered
+
+
+@pytest.mark.parametrize(('path', 'template_name'), (
+    ('/', 'plain.html'),
+    ('/plain', 'plain.html'),
+    ('/fetch', 'fetch.html'),
+    ('/jquery', 'jquery.html'),
+))
+def test_index(app, client, path, template_name):
+    def check(sender, template, context):
+        assert template.name == template_name
+
+    with template_rendered.connected_to(check, app):
+        client.get(path)
+
+
+@pytest.mark.parametrize(('a', 'b', 'result'), (
+    (2, 3, 5),
+    (2.5, 3, 5.5),
+    (2, None, 2),
+    (2, 'b', 2),
+))
+def test_add(client, a, b, result):
+    response = client.post('/add', data={'a': a, 'b': b})
+    assert response.get_json()['result'] == result
diff --git a/examples/tutorial/README.rst b/examples/tutorial/README.rst
index e0c44b61..1afb1ebd 100644
--- a/examples/tutorial/README.rst
+++ b/examples/tutorial/README.rst
@@ -65,12 +65,11 @@ Test
 
 ::
 
-    pip install pytest
+    pip install '.[test]'
     pytest
 
 Run with coverage report::
 
-    pip install pytest coverage
     coverage run -m pytest
     coverage report
     coverage html  # open htmlcov/index.html in a browser
diff --git a/examples/tutorial/flaskr/auth.py b/examples/tutorial/flaskr/auth.py
index d86095bf..e8cd2940 100644
--- a/examples/tutorial/flaskr/auth.py
+++ b/examples/tutorial/flaskr/auth.py
@@ -56,7 +56,7 @@ def register():
         elif db.execute(
             'SELECT id FROM user WHERE username = ?', (username,)
         ).fetchone() is not None:
-            error = 'User {} is already registered.'.format(username)
+            error = 'User {0} is already registered.'.format(username)
 
         if error is None:
             # the name is available, store it in the database and go to
diff --git a/examples/tutorial/setup.cfg b/examples/tutorial/setup.cfg
index b0cc972d..3e47794e 100644
--- a/examples/tutorial/setup.cfg
+++ b/examples/tutorial/setup.cfg
@@ -2,7 +2,7 @@
 license_file = LICENSE
 
 [bdist_wheel]
-universal = False
+universal = True
 
 [tool:pytest]
 testpaths = tests
diff --git a/examples/tutorial/setup.py b/examples/tutorial/setup.py
index 52a282a2..460d789b 100644
--- a/examples/tutorial/setup.py
+++ b/examples/tutorial/setup.py
@@ -20,4 +20,10 @@ setup(
     install_requires=[
         'flask',
     ],
+    extras_require={
+        'test': [
+            'pytest',
+            'coverage',
+        ],
+    },
 )
diff --git a/tox.ini b/tox.ini
index cbc72ade..5818fa89 100644
--- a/tox.ini
+++ b/tox.ini
@@ -31,7 +31,8 @@ deps =
 
 commands =
     # the examples need to be installed to test successfully
-    pip install -e examples/tutorial -q
+    pip install -q -e examples/tutorial[test]
+    pip install -q -e examples/javascript[test]
 
     # pytest-cov doesn't seem to play nice with -p
     coverage run -p -m pytest tests examples