add javascript ajax example

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