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</> htmx - high power tools for HTML

&lt;/&gt; htmx

high power tools for HTML

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htmx allows you to access AJAX, CSS Transitions, WebSockets and Server Sent Events directly in HTML, using attributes, so you can build modern user interfaces with the simplicity and power of hypertext

htmx is small (~14k min.gz'd), dependency-free, extendable & IE11 compatible


  • Why should only <a> and <form> be able to make HTTP requests?
  • Why should only click & submit events trigger them?
  • Why should only GET & POST be available?
  • Why should you only be able to replace the entire screen?

By removing these arbitrary constraints htmx completes HTML as a hypertext

quick start

  <script src="[email protected]"></script>
  <!-- have a button POST a click via AJAX -->
  <button hx-post="/clicked" hx-swap="outerHTML">
    Click Me

The hx-post and hx-swap attributes tell htmx:

"When a user clicks on this button, issue an AJAX request to /clicked, and replace the entire button with the response"

htmx is the successor to intercooler.js

installing as a node package

To install using npm:

npm install --save

Note there is an old broken package called htmx. This is

website & docs


  • please write code, including tests, in ES5 for IE 11 compatibility
  • please include test cases in /test and docs in /www
  • if you are adding a feature, consider doing it as an extension instead to keep the core htmx code tidy
  • development pull requests should be against the dev branch, docs fixes can be made directly against master
  • No time? Then become a sponsor

hacking guide

To develop htmx locally, you will need to install the development dependencies.

Requires Node 15.


npm install

Then, run a web server in the root.

This is easiest with:

npx serve

You can then run the test suite by navigating to:

At this point you can modify /src/htmx.js to add features, and then add tests in the appropriate area under /test.

  • /test/index.html - the root test page from which all other tests are included
  • /test/attributes - attribute specific tests
  • /test/core - core functionality tests
  • /test/core/regressions.js - regression tests
  • /test/ext - extension tests
  • /test/manual - manual tests that cannot be automated

htmx uses the mocha testing framework, the chai assertion framework and sinon to mock out AJAX requests. They are all OK.


javascript fatigue:
longing for a hypertext
already in hand