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    jQuery Pjax

    pushState + ajax = pjax
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    pjax = pushState + ajax

    pjax is a jQuery plugin that uses ajax and pushState to deliver a fast browsing experience with real permalinks, page titles, and a working back button.

    pjax works by fetching HTML from your server via ajax and replacing the content of a container element on your page with the loaded HTML. It then updates the current URL in the browser using pushState. This results in faster page navigation for two reasons:

    • No page resources (JS, CSS) get re-executed or re-applied;
    • If the server is configured for pjax, it can render only partial page contents and thus avoid the potentially costly full layout render.

    Status of this project

    jquery-pjax is largely unmaintained at this point. It might continue to receive important bug fixes, but its feature set is frozen and it's unlikely that it will get new features or enhancements.

    Installation

    pjax depends on jQuery 1.8 or higher.

    npm

    $ npm install jquery-pjax
    

    standalone script

    Download and include jquery.pjax.js in your web page:

    curl -LO https://raw.github.com/defunkt/jquery-pjax/master/jquery.pjax.js
    

    Usage

    $.fn.pjax

    The simplest and most common use of pjax looks like this:

    $(document).pjax('a', '#pjax-container')
    

    This will enable pjax on all links on the page and designate the container as #pjax-container.

    If you are migrating an existing site, you probably don't want to enable pjax everywhere just yet. Instead of using a global selector like a, try annotating pjaxable links with data-pjax, then use 'a[data-pjax]' as your selector. Or, try this selector that matches any <a data-pjax href=> links inside a <div data-pjax> container:

    $(document).pjax('[data-pjax] a, a[data-pjax]', '#pjax-container')
    

    Server-side configuration

    Ideally, your server should detect pjax requests by looking at the special X-PJAX HTTP header, and render only the HTML meant to replace the contents of the container element (#pjax-container in our example) without the rest of the page layout. Here is an example of how this might be done in Ruby on Rails:

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

    If you'd like a more automatic solution than pjax for Rails check out Turbolinks.

    Check if there is a pjax plugin for your favorite server framework.

    Also check out RailsCasts #294: Playing with PJAX.

    Arguments

    The synopsis for the $.fn.pjax function is:

    $(document).pjax(selector, [container], options)
    
    1. selector is a string to be used for click event delegation.
    2. container is a string selector that uniquely identifies the pjax container.
    3. options is an object with keys described below.
    pjax options
    key default description
    timeout 650 ajax timeout in milliseconds after which a full refresh is forced
    push true use pushState to add a browser history entry upon navigation
    replace false replace URL without adding browser history entry
    maxCacheLength 20 maximum cache size for previous container contents
    version a string or function returning the current pjax version
    scrollTo 0 vertical position to scroll to after navigation. To avoid changing scroll position, pass false.
    type "GET" see $.ajax
    dataType "html" see $.ajax
    container CSS selector for the element where content should be replaced
    url link.href a string or function that returns the URL for the ajax request
    target link eventually the relatedTarget value for pjax events
    fragment CSS selector for the fragment to extract from ajax response

    You can change the defaults globally by writing to the $.pjax.defaults object:

    $.pjax.defaults.timeout = 1200
    

    $.pjax.click

    This is a lower level function used by $.fn.pjax itself. It allows you to get a little more control over the pjax event handling.

    This example uses the current click context to set an ancestor element as the container:

    if ($.support.pjax) {
      $(document).on('click', 'a[data-pjax]', function(event) {
        var container = $(this).closest('[data-pjax-container]')
        var containerSelector = '#' + container.id
        $.pjax.click(event, {container: containerSelector})
      })
    }
    

    NOTE Use the explicit $.support.pjax guard. We aren't using $.fn.pjax so we should avoid binding this event handler unless the browser is actually going to use pjax.

    $.pjax.submit

    Submits a form via pjax.

    $(document).on('submit', 'form[data-pjax]', function(event) {
      $.pjax.submit(event, '#pjax-container')
    })
    

    $.pjax.reload

    Initiates a request for the current URL to the server using pjax mechanism and replaces the container with the response. Does not add a browser history entry.

    $.pjax.reload('#pjax-container', options)
    

    $.pjax

    Manual pjax invocation. Used mainly when you want to start a pjax request in a handler that didn't originate from a click. If you can get access to a click event, consider $.pjax.click(event) instead.

    function applyFilters() {
      var url = urlForFilters()
      $.pjax({url: url, container: '#pjax-container'})
    }
    

    Events

    All pjax events except pjax:click & pjax:clicked are fired from the pjax container element.

    event cancel arguments notes
    event lifecycle upon following a pjaxed link
    pjax:click ✔︎ options fires from a link that got activated; cancel to prevent pjax
    pjax:beforeSend ✔︎ xhr, options can set XHR headers
    pjax:start xhr, options
    pjax:send xhr, options
    pjax:clicked options fires after pjax has started from a link that got clicked
    pjax:beforeReplace contents, options before replacing HTML with content loaded from the server
    pjax:success data, status, xhr, options after replacing HTML content loaded from the server
    pjax:timeout ✔︎ xhr, options fires after options.timeout; will hard refresh unless canceled
    pjax:error ✔︎ xhr, textStatus, error, options on ajax error; will hard refresh unless canceled
    pjax:complete xhr, textStatus, options always fires after ajax, regardless of result
    pjax:end xhr, options
    event lifecycle on browser Back/Forward navigation
    pjax:popstate event direction property: "back"/"forward"
    pjax:start null, options before replacing content
    pjax:beforeReplace contents, options right before replacing HTML with content from cache
    pjax:end null, options after replacing content

    pjax:send & pjax:complete are a good pair of events to use if you are implementing a loading indicator. They'll only be triggered if an actual XHR request is made, not if the content is loaded from cache:

    $(document).on('pjax:send', function() {
      $('#loading').show()
    })
    $(document).on('pjax:complete', function() {
      $('#loading').hide()
    })
    

    An example of canceling a pjax:timeout event would be to disable the fallback timeout behavior if a spinner is being shown:

    $(document).on('pjax:timeout', function(event) {
      // Prevent default timeout redirection behavior
      event.preventDefault()
    })
    

    Advanced configuration

    Reinitializing plugins/widget on new page content

    The whole point of pjax is that it fetches and inserts new content without refreshing the page. However, other jQuery plugins or libraries that are set to react on page loaded event (such as DOMContentLoaded) will not pick up on these changes. Therefore, it's usually a good idea to configure these plugins to reinitialize in the scope of the updated page content. This can be done like so:

    $(document).on('ready pjax:end', function(event) {
      $(event.target).initializeMyPlugin()
    })
    

    This will make $.fn.initializeMyPlugin() be called at the document level on normal page load, and on the container level after any pjax navigation (either after clicking on a link or going Back in the browser).

    Response types that force a reload

    By default, pjax will force a full reload of the page if it receives one of the following responses from the server:

    • Page content that includes <html> when fragment selector wasn't explicitly configured. Pjax presumes that the server's response hasn't been properly configured for pjax. If fragment pjax option is given, pjax will extract the content based on that selector.

    • Page content that is blank. Pjax assumes that the server is unable to deliver proper pjax contents.

    • HTTP response code that is 4xx or 5xx, indicating some server error.

    Affecting the browser URL

    If the server needs to affect the URL which will appear in the browser URL after pjax navigation (like HTTP redirects work for normal requests), it can set the X-PJAX-URL header:

    def index
      request.headers['X-PJAX-URL'] = "http://example.com/hello"
    end
    

    Layout Reloading

    Layouts can be forced to do a hard reload when assets or html changes.

    First set the initial layout version in your header with a custom meta tag.

    <meta http-equiv="x-pjax-version" content="v123">
    

    Then from the server side, set the X-PJAX-Version header to the same.

    if request.headers['X-PJAX']
      response.headers['X-PJAX-Version'] = "v123"
    end
    

    Deploying a deploy, bumping the version constant to force clients to do a full reload the next request getting the new layout and assets.

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