pushState + ajax = pjax

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      (   '._)
       |'-- |
     _.\___/_   ___pjax___
   ."\> \Y/|<'.  '._.-'
  /  \ \_\/ /  '-' /
  | --'\_/|/ |   _/
  |___.-' |  |`'`
    |     |  |
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   /__./` | |
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      `-"--'---'

what is it?

pjax loads HTML from your server into the current page without a full reload. It's ajax with real permalinks, page titles, and a working back button that fully degrades.

pjax enhances the browsing experience - nothing more.

You can find a demo on http://pjax.heroku.com/

three ways to pjax on the client side:

One. Functionally obtrusive, loading the href with ajax into data-pjax:

<a href='/explore' data-pjax='#main'>Explore</a>

$('a[data-pjax]').pjax()

Two. Slightly obtrusive, passing a container and binding an error handler:

<a href='/explore' class='js-pjax'>Explore</a>

$('.js-pjax').pjax('#main')

$('#main').live('pjax:error', function(e, xhr, err) {
  $('.error').text('Something went wrong: ' + err)
})

Three. Unobtrusive, showing a 'loading' spinner:

<div id='main'>
  <div class='loader' style='display:none'><img src='spin.gif'></div>
  <div class='tabs'>
    <a href='/explore'>Explore</a>
    <a href='/help'>Help</a>
  </div>
</div>

$('a').pjax('#main').live('click', function(){
  $(this).showLoader()
})

$(link).pjax( container, options )

The $(link).pjax() function accepts a container, an options object, or both. The container MUST be a string selector - this is because we cannot persist jQuery objects using the History API between page loads.

The options are the same as jQuery's $.ajax options with the following additions:

• container - The String selector of the container to load the reponse body. Must be a String.
• target - The Element that was clicked to start the pjax call.
• push - Whether to pushState the URL. Default: true (of course)
• replace - Whether to replaceState the URL. Default: false
• timeout - pjax sets this low, <1s. Set this higher if using a custom error handler. It's ms, so something like timeout: 2000
• fragment - A String selector that specifies a sub-element to be pulled out of the response HTML and inserted into the container. Useful if the server always returns full HTML pages.

$.pjax( options )

You can also just call $.pjax directly. It acts much like $.ajax, even returning the same thing and accepting the same options.

The pjax-specific keys listed in the $(link).pjax() section work here as well.

This pjax call:

$.pjax({
  url: '/authors',
  container: '#main'
})

Roughly translates into this ajax call:

$.ajax({
  url: '/authors',
  dataType: 'html',
  beforeSend: function(xhr){
    xhr.setRequestHeader('X-PJAX', 'true')
  },
  success: function(data){
    $('#main').html(data)
    history.pushState(null, $(data).filter('title').text(), '/authors')
  })
})

pjax on the server side

You'll want to give pjax requests a 'chrome-less' version of your page. That is, the page without any layout.

As you can see in the "ajax call" example above, pjax sets a custom 'X-PJAX' header to 'true' when it makes an ajax request to make detecting it easy.

In Rails, check for request.headers['X-PJAX']:

def my_page
  if request.headers['X-PJAX']
    render :layout => false
  end
end

Or as a before filter in application controller:

layout :set_layout

private
  def set_layout
    if request.headers['X-PJAX']
      false
    else
      "application"
    end
  end

Rails: https://github.com/rails/pjax_rails

Django: https://github.com/jacobian/django-pjax

Asp.Net MVC3: http://biasecurities.com/blog/2011/using-pjax-with-asp-net-mvc3/

page titles

Your HTML should also include a <title> tag if you want page titles to work.

When using a page fragment, pjax will check the fragment DOM element for a title or data-title attribute and use any value it finds.

events

pjax will fire two events on the container you've asked it to load your reponse body into:

• pjax:start - Fired when a pjax ajax request begins.
• pjax:end - Fired when a pjax ajax request ends.

This allows you to, say, display a loading indicator upon pjaxing:

$('a.pjax').pjax('#main')
$('#main')
  .on('pjax:start', function() { $('#loading').show() })
  .on('pjax:end',   function() { $('#loading').hide() })

Because these events bubble, you can also set them on the document:

$('a.pjax').pjax()
$(document)
  .on('pjax:start', function() { $('#loading').show() })
  .on('pjax:end',   function() { $('#loading').hide() })

In addition, custom events are added to complement $.ajax's callbacks.

• pjax:beforeSend - Fired before the pjax request begins. Returning false will abort the request.
• 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.
• pjax:timeout - Fired if after timeout is reached. Returning false will disable the fallback and will wait indefinitely until the response returns.

CAUTION Callback handlers passed to $.pjax cannot be persisted across full page reloads. Its recommended you use custom events instead.

browser support

pjax only works with browsers that support the history.pushState API.

For a table of supported browsers see: http://caniuse.com/#search=pushstate

To check if pjax is supported, use the $.support.pjax boolean.

When pjax is not supported, $('a').pjax() calls will do nothing (aka links work normally) and $.pjax({url:url}) calls will redirect to the given URL.

install it

$ cd path/to/js
$ wget https://raw.github.com/defunkt/jquery-pjax/master/jquery.pjax.js

Then, in your HTML:

<script src="path/to/js/jquery.pjax.js"></script>

Replace path/to/js with the path to your JavaScript directory, e.g. public/javascripts.

minimize it

curl \
  -d output_info=compiled_code \
  -d compilation_level=SIMPLE_OPTIMIZATIONS \
  -d code_url=https://github.com/defunkt/jquery-pjax/raw/master/jquery.pjax.js \
  http://closure-compiler.appspot.com/compile