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Pjax

Easily enable fast Ajax navigation on any website (using pushState + xhr)

Pjax is a jQuery plugin a standalone JavaScript module that uses ajax (XmlHttpRequest) and pushState() to deliver a fast browsing experience.

It allow you to completely transform user experience of standard websites (server side generated or static ones) to make them feel they browse an app. Especially for user that have low bandwidth connection.

No more full page reload. No more lots of HTTP request.

No tests or Demo ?

There is still some work to make this repo sexy with tests & simple demo.
Actually there is a WIP branch where I'm adding lot of tests

For now you can see this running on my website, with sexy CSS animations when switching pages.

How Pjax works

Pjax loads page using ajax & updates the browser's current url using pushState without reloading your page's layout or any resources (js, css), giving a fast page load. But under the hood, it's just ONE http request with a pushState() call. Obviously, for browsers that don't support pushState() Pjax fully degrades (yeah, it doesn't do anything at all).

It simply works with all permalinks & can update all parts of the page you want (including html metas, title, navigation state).

  • It's not limited to one container, like jQuery-Pjax is,
  • It fully support browser history (back & forward buttons),
  • It will support keyboard browsing (@todo),
  • Automatically fallback to classic navigation for externals pages (thanks to Capitain Obvious help),
  • Automatically fallback to classic navigation for internals pages that will not have the appropriated DOM tree,
  • You can add pretty cool CSS transitions (animations) very easily.
  • It's around 3kb (minified & gzipped).

Under the hood

  • It listen to every clicks on links you want (by default all of them),
  • When a internal link hitted, Pjax grabs HTML from your server via ajax,
  • Pjax render pages DOM tree (without loading any resources - images, css, js...)
  • It check if all defined parts can be replaced:
    • if page doesn't suit requirement, classic navigation used,
    • if page suits requirement, Pjax does all defined DOM replacements
  • Then, it updates the browser's current url using pushState

Overview

Pjax is fully automatic. You won't need to setup anything on the existing HTML. You just need to designate some elements on your page that will be replaced when you navigate your site.

Consider the following page.

<!doctype html>
<html>
<head>
  <!-- metas, title, styles, ... -->
</head>
<body>
  <header class="my-Header"><nav><!-- a .is-active is in there --></nav></header>
  <section class="my-Content">
    Sha blah <a href="/blah ">blah</a>.
  </section>
  <aside class="my-Sidebar">Sidebar stuff</aside>
  <footer class="my-Footer"></footer>
  <script src="onDomReadystuff.js"></script>
  <script><!-- analytics --></script>
</body>
</html>

We want Pjax to grab the url /blah then replace .my-Content with whatever it gets back. Oh and the <nav> (that contains a status marker somewhere) can be updated too (or stay the same, as you wish). And also the <aside> please. So we want to update [".my-Header", ".my-Content", ".my-Sidebar"], without reloading styles nor scripts.

We do this by telling Pjax to listen on a tags and use CSS selectors defined above (without forgetting minimal meta):

new Pjax({ selectors: ["title", ".my-Header", ".my-Content", ".my-Sidebar"] })

Now when someone in a Pjax-compatible browser clicks "blah" the content of all selectors will be replaced with the one found in the "blah" content.

Magic! For real! There is completely no need to do anything on server side!

Differences with jQuery-pjax

  • No jQuery dependency,
  • Not limited to a container,
  • No server side requirements,
  • Works for CommonJS environment (browserify), AMD (RequireJS) or even globally,
  • Allow page transition with CSS animations,
  • Can be easily hacked since every method is public (so overridable)

Installation

You can install pjax from npm

$ npm install pjax

Or using bower

$ bower install pjax

Pjax can obviously be downloaded directly.

No dependencies

There is nothing you need. No jQuery or something.

Compatibility

Pjax only works with browsers that support the history.pushState API. When the API isn't supported Pjax goes into fallback mode (it just does nothing).

To see if Pjax is actually supported by your browser, use Pjax.isSupported().

Usage

new Pjax()

Let's talk more about the most basic way to get started:

new Pjax({
  elements: "a" // default is "a[href], form[action]"
, selectors: ["title", ".my-Header", ".my-Content", ".my-Sidebar"]
})

This will enable Pjax on all links and designate the part to replace using CSS selectors "title", ".my-Header", ".my-Content", ".my-Sidebar".

For some reason, you might want to just target some elements to apply Pjax behavior. In that case, you can 2 differents things:

  • use a custom selector like "a.js-Pjax" or ".js-Pjax a" depending on what you want.
  • override Pjax.prototype.getElements that just basically querSelectorAll the elements option. In this function you just need to return a NodeList.
// use case 1
new Pjax({ elements: "a.js-Pjax" })


// use case 2
Pjax.prototype.getElements = function() {
  return document.getElementsByClassName(".js-Pjax")
}

new Pjax({})

When instanciating a Pjax object, you need to pass all options as an object:

Options

elements (String, default "a[href], form[action]")

CSS Selector to use to retrieve links to apply Pjax

selectors (Array, default ["title", ".js-Pjax"])

CSS Selectors to replace. If a query returns multiples items, it will just keep the index.

Example of what you can do:

<!doctype html>
<html>
<head>
  <title>Page title</title>
</head>
<body>
  <header class="js-Pjax"></header>
  <section class="js-Pjax">...</section>
  <footer class="my-Footer"></footer>
  <script>...</script>
</body>
</html>

This example is correct and should work "as expected". If there is not the same amount of DOM element from current page and new page, the Pjax behavior will fallback to normal page load.

switches (Object, default {})

Objects containing callbacks that can be used to switch old element with new element. Keys should be one of the defined selector.

Examples:

new Pjax({
  selectors: ["title", ".Navbar", ".js-Pjax"]
, switches: {
    // "title": Pjax.switches.outerHTML // default behavior
    ".Navbar": function(oldEl, newEl, options) {
      // here it's a stupid example since it's the default behavior too
      oldEl.outerHTML = newEl.outerHTML
      this.onSwitch()
    },

    ".js-Pjax": Pjax.switches.sideBySide
  }
})

Callbacks are binded to Pjax instance itself to allow you to reuse it (ex: this.onSwitch())

Existing switches callback
  • Pjax.switches.outerHTML: default behavior, replace elements using outerHTML
  • Pjax.switches.innerHTML: replace elements using innerHTML & copy className too
  • Pjax.switches.sideBySide: smart replacement that allow you to have both elements in the same parent when you want to use CSS animations. Old elements are removed when all childs have been fully animated (animationEnd event triggered)
Create a switch callback

Your function can do whatever you want, but you need to:

  • replace oldEl content by newEl content in some fashion
  • call this.onSwitch() to trigger attached callback.

Here is the default behavior as example

function(oldEl, newEl, pjaxRequestOptions, switchesClasses) {
  oldEl.outerHTML = newEl.outerHTML
  this.onSwitch()
}
switchesOptions (Object, default {})

This are options that can be used during switch by switchers ( for now, only Pjax.switches.sideBySide use it). Very convenient when you use something like Animate.css with or without WOW.js.

new Pjax({
  selectors: ["title", ".js-Pjax"]
, switches: {
    ".js-Pjax": Pjax.switches.sideBySide
  }
, switchesClasses: {
    ".js-Pjax": {
      classNames: {
        // class added on the element that will be removed
        remove: "Animated Animated--reverse Animate--fast Animate--noDelay"
        // class added on the element that will be added
      , add: "Animated"
        // class added on the element when it go backward
      , backward: "Animate--slideInRight"
        // class added on the element when it go forward (used for new page too)
      , forward: "Animate--slideInLeft"
      }
    , callbacks: {
        // to make a nice transition with 2 pages as the same time
        // we are playing with absolute positioning for element we are removing
        // & we need live metrics to have something great
        // see associated CSS below
        removeElement: function(el) {
          el.style.marginLeft = "-" + (el.getBoundingClientRect().width/2) + "px"
        }
      }
    }
})

Note that remove class include Animated--reverse which is a simple way to not have to create duplicate transition for (slideIn + reverse => slideOut).

The following CSS will be required to make something nice

/*
  if your content elements doesn't have a fixed width,
  you can get issue when absolute positioning will be used
  so you will need that rules
*/
.js-Pjax { position: relative } /* parent element where switch will be made */

  .js-Pjax-child { width: 100% }

  /* position for the elements that will be removed */
  .js-Pjax-remove {
    position: absolute;
    left: 50%;
    /* transform: translateX(-50%) */
    /* transform can't be used since we already use generic translate for the remove effect (eg animate.css) */
    /* margin-left: -width/2; // made with js */
    /* you can totally drop the margin-left thing from switchesOptions if you use custom animations */
  }

/* CSS animations */
.Animated {
  animation-fill-mode: both;
  animation-duration: 1s;
}

  .Animated--reverse { animation-direction: reverse }

  .Animate--fast { animation-duration: .5s }
  .Animate--noDelay { animation-delay: 0s !important;  }

  .Animate--slideInRight { animation-name: Animation-slideInRight }
  @keyframes Animation-slideInRight {
    0% {
      opacity: 0;
      transform: translateX(100rem);
    }

    100% {
      transform: translateX(0);
    }
  }

  .Animate--slideInLeft { animation-name: Animation-slideInLeft }
  @keyframes Animation-slideInLeft {
    0% {
      opacity: 0;
      transform: translateX(-100rem);
    }

    100% {
      transform: translateX(0);
    }
  }

To get understand this CSS, here is a HTML snippet

<!doctype html>
<html>
<head>
  <title>Page title</title>
</head>
<body>
  <section class="js-Pjax">
    <div class="js-Pjax-child">
      Your content here
    </div>
    <!--
    when switching will be made you will have the following tree
    <div class="js-Pjax-child js-Pjax-remove Animate...">
      Your OLD content here
    </div>
    <div class="js-Pjax-child js-Pjax-add Animate...">
      Your NEW content here
    </div>
    -->
  </section>
  <script>...</script>
</body>
</html>
history (Boolean, default true)

Enable pushState. Only disable if you are crazy. Internaly, this option is used when popstate is used (to not pushState again). You should forget that option.

analytics (Function, default to a function that push _gaq trackPageview or send ga pageview

Function that allow you to add behavior for analytics. By default it try to track a pageview with Google Analytics. It's called every time a page is switched, even for history buttons.

scrollTo (Integer, default to 0)

Value (in px) to scrollTo when a page is switched.

debug (Boolean, default to false)

Enable verbose mode & doesn't use fallback when there is an error. Useful to debug page layout differences.

Extend Pjax

Pjax prototype & utilities methods can be used & changed so you can patch or hack Pjax behavior, as you wish.

Here is a summary of functions:

  • Pjax.isSupported (function()): return wheter or not the browser handle pushState correctly

  • Pjax.on (function(els, events, listener, useCapture)): addEventListener, that handles NodeList & supports space separated event name

  • Pjax.off (function(els, events, listener, useCapture)): removeEventListener, that handles NodeList & supports space separated event name

  • Pjax.trigger (function(els, events)): fireEvent, that handles NodeList & supports space separated event name

  • Pjax.clone (function(obj)): clone object

  • Pjax.executeScripts (function(el)): execute scripts that are inside an element (script src or inline scripts through Pjax.evalScript)

  • Pjax.evalScript (function(el)): execute inline script. Don't execute a script if it contains document.write.

  • Pjax.prototype.log (function()): console.log function that is enable/disabled by debug option

  • Pjax.prototype.getElements (function(el)): retrieve elements to attach Pjax behavior

  • Pjax.prototype.parseDOM (function(el)): parse DOM to attach behavior using Pjax.prototype.getElements & Pjax.prototype.attachLink

  • Pjax.prototype.attachLink (function(el)): attach Pjax behavior to a link

  • Pjax.prototype.forEachSelectors (function(cb, context, DOMcontext)): call a function for each selectors defined

  • Pjax.prototype.switchSelectors (function(selectors, fromEl, toEl, options)): loop on selectors to switch elements

  • Pjax.prototype.latestChance (function(href)): when everything is fucked up, it's our only hope (just call window.location = href)

  • Pjax.prototype.onSwitch (function()): callback triggered when elements are switched, for now it's just trigger a window resize event (lots of lib are listening to this event to draw stuff)

  • Pjax.prototype.loadContent (function(html, options)): switch elements for each selectors

  • Pjax.prototype.doRequest (function(location, callback)): make the ajax request to grab page from the server

  • Pjax.prototype.loadUrl (function(href, options)): do the ajax request, handle html results & eventually handle browser history, analytics & scroll.

Events

Pjax fires a number of events regardless of how its invoked.

All events are fired from the document, not the link was clicked.

Ajax related events

  • pjax:send - Fired after the Pjax request begins.
  • pjax:complete - Fired after the Pjax request finishes.
  • pjax:success - Fired after the Pjax request succeeds.
  • pjax:error - Fired after the Pjax request fails. Returning false will prevent the the fallback redirect.

send and complete are a good pair of events to use if you are implementing a loading indicator (eg: topbar)

$(document).on('pjax:send', topbar.show)
$(document).on('pjax:complete', topbar.hide)

Note about DOM ready state

Most of the time, you have code attached & related to the current DOM, that you only execute when page/dom is ready. Since Pjax doesn't magically rexecute you previous code each time you load a page, you need to make a simple thing to rexecute appropriate code:

function whenDOMReady() {
  // do you stuff
}

whenDOMReady()

new Pjax()

document.addEventListener("pjax:success", whenDOMReady)

Note: Don't create the Pjax in the whenDOMReady function.

For my concern & usage, I js-Pjaxify all body children, including stuff like navigation & footer (to get navigation state easily updated). So attached behavior are rexecuted each time a page is loaded, like in the snippet above.

If you want to just update a specific part (it's totally a good idea), you can just add the DOM related code in a function & rexecute this function when "pjax:success" event is done.

// do your global stuff
//... dom ready blah blah

function whenContainerReady() {
  // do your container related stuff
}
whenContainerReady()

new Pjax()

document.addEventListener("pjax:success", whenContainerReady)

FAQ

Q: Disqus doesn't work anymore, how can I fix that ?

A: There is a few things you need to do:

  • wrap your disqus snippet into a dom element that you will add to the selector arra (or just wrap it with class="js-Pjax") & be sure to have a least the empty wrapper on each page (to avoid differences of DOM between pages)
  • edit your disqus snippet like the one below

Disqus snippet before pjax integration

<script>
  var disqus_shortname = 'YOURSHORTNAME'
  , disqus_identifier = 'PAGEID'
  , disqus_url = 'PAGEURL'
  , disqus_script = 'embed.js'
  (function(d,s) {
  s = d.createElement('script');s.async=1;s.src = '//' + disqus_shortname + '.disqus.com/'+disqus_script;
  (d.getElementsByTagName('head')[0]).appendChild(s);
  })(document)
</script>

Disqus snippet after Pjax integration

<div class="js-Pjax"><!-- need to be here on every pjaxified page, even if empty -->
<!-- if (blah blah) { // eventual server side test to know wheter or not you include this script -->
  <script>
    var disqus_shortname = 'YOURSHORTNAME'
    , disqus_identifier = 'PAGEID'
    , disqus_url = 'PAGEURL'
    , disqus_script = 'embed.js'

    // here we will only load the disqus <script> if not already loaded
    if (!window.DISQUS) {
      (function(d,s) {
      s = d.createElement('script');s.async=1;s.src = '//' + disqus_shortname + '.disqus.com/'+disqus_script;
      (d.getElementsByTagName('head')[0]).appendChild(s);
      })(document)
    }
    // if disqus <script> already loaded, we just reset disqus the right way
    // see http://help.disqus.com/customer/portal/articles/472107-using-disqus-on-ajax-sites
    else {
      DISQUS.reset({
        reload: true,
        config: function () {
          this.page.identifier = disqus_identifier
          this.page.url = disqus_url
        }
      })
    }
  </script>
<!-- } -->
</div>

Note: The thing you need to understand is that Pjax handle inline <script> only for container you are reloading.

Changelog

Contributing

Please read the file nobody reads (make me lie) CONTRIBUTING.md

tl;dr;

Fork, clone, then

$ npm i -g gulp
$ npm i
$ gulp

Now you can work on the file, then make a commit and a push something when gulp doesn't show any error. Thanks.

License