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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 grabbing html from your server via ajax and replacing the content of a container on your page with the ajax'd html. It then updates the browser's current url using pushState without reloading your page's layout or any resources (js, css), giving the appearance of a fast, full page load. But really it's just ajax and pushState.
For browsers that don't support pushState pjax fully degrades.
pjax is not fully automatic. You'll need to setup and designate a containing element on your page that will be replaced when you navigate your site.
Consider the following page.
<!DOCTYPE html>
<html>
<head>
<!-- styles, scripts, etc -->
</head>
<body>
<h1>My Site</h1>
<div class="container" id="pjax-container">
Go to <a href="/page/2">next page</a>.
</div>
</body>
</html>We want pjax to grab the url /page/2 then replace #pjax-container with whatever it gets back. No styles or scripts will be reloaded and even the h1 can stay the same - we just want to change the #pjax-container element.
We do this by telling pjax to listen on a tags and use #pjax-container as the target container:
$(document).pjax('a', '#pjax-container')Now when someone in a pjax-compatible browser clicks "next page" the content of #pjax-container will be replaced with the body of /page/2.
Magic! Almost. You still need to configure your server to look for pjax requests and send back pjax-specific content.
The pjax ajax request sends an X-PJAX header so in this example (and in most cases) we want to return just the content of the page without any layout for any requests with that header.
Here's what it might look like in Rails:
def index
if request.headers['X-PJAX']
render :layout => false
end
endIf you'd like a more automatic solution than pjax for Rails check out Turbolinks.
Also check out RailsCasts #294 : Playing with PJAX
Via bower.
$ bower install jquery-pjax
Or add jquery-pjax to your apps bower.json.
"dependencies": {
"jquery-pjax": "latest"
}pjax can be downloaded directly into your app's public directory - just be sure you've loaded jQuery first.
curl -O https://raw.github.com/defunkt/jquery-pjax/master/jquery.pjax.js
WARNING Do not hotlink the raw script url. GitHub is not a CDN.
Requires jQuery 1.8.x or higher.
pjax only works with browsers that support the history.pushState API. When the API isn't supported pjax goes into fallback mode: $.fn.pjax calls will be a no-op and $.pjax will hard load the given url. This mode targets the browser requirements of the jQuery version being used.
For debugging purposes, you can intentionally disable pjax even if the browser supports pushState. Just call $.pjax.disable(). To see if pjax is actually supports pushState, check $.support.pjax.
Let's talk more about the most basic way to get started:
$(document).pjax('a', '#pjax-container')This will enable pjax on all links 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')When invoking $.fn.pjax there are a few different argument styles you can use:
$(document).pjax(delegation selector, options object)$(document).pjax(delegation selector, container selector, options object)
In other words:
- The first argument must always be a
Stringselector used for delegation. - The second argument can either be a
Stringcontainer selector or an options object. - If there are three arguments the second must be the
Stringcontainer selector and the third must be the options object.
This is a lower level function used by $.fn.pjax itself. It allows you to get a little more control over the pjax event handling.
This example uses the current click context to set an ancestor as the container:
if ($.support.pjax) {
$(document).on('click', 'a[data-pjax]', function(event) {
var container = $(this).closest('[data-pjax-container]')
$.pjax.click(event, {container: container})
})
}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.
Submits a form via pjax. This function is experimental but GitHub uses it on Gist so give it a shot!
$(document).on('submit', 'form[data-pjax]', function(event) {
$.pjax.submit(event, '#pjax-container')
})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'})
}pjax fires a number of events regardless of how its invoked.
All events are fired from the container, not the link was clicked.
pjax:start- Fired when pjaxing begins.pjax:end- Fired when pjaxing ends.pjax:click- Fired when pjaxified link is clicked.
This pair events fire anytime a pjax request starts and finishes. This includes pjaxing on popstate and when pages are loaded from cache instead of making a request.
pjax:beforeSend- Fired before the pjax request begins. Returning false will abort the request.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.pjax:timeout- Fired if after timeout is reached. Returning false will disable the fallback and will wait indefinitely until the response returns.
send and complete are a good pair of events to use if you are implementing a loading indicator. They'll only be triggered if an actual request is made, not if it's loaded from cache.
$(document).on('pjax:send', function() {
$('#loading').show()
})
$(document).on('pjax:complete', function() {
$('#loading').hide()
})Another protip: disable the fallback timeout behavior if a spinner is being shown.
$(document).on('pjax:timeout', function(event) {
// Prevent default timeout redirection behavior
event.preventDefault()
})Server configuration will vary between languages and frameworks. The following example shows how you might configure Rails.
def index
if request.headers['X-PJAX']
render :layout => false
end
endAn X-PJAX request header is set to differentiate a pjax request from normal XHR requests. In this case, if the request is pjax, we skip the layout html and just render the inner contents of the container.
Check if your favorite server framework supports pjax here: https://gist.github.com/4283721
Layouts can be forced to do a hard reload 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"
endDeploying a deploy, bumping the version constant to force clients to do a full reload the next request getting the new layout and assets.
Pre 1.0 versions used an older style syntax that was analogous to the now deprecated $.fn.live api. The current api is based off $.fn.on.
$('a[data-pjax]').pjax('#pjax-container')Expanded to
$('a[data-pjax]').live('click', function(event) {
$.pjax.click(event, '#pjax-container')
})The new api
$(document).pjax('a[data-pjax]', '#pjax-container')Which is roughly the same as
$(document).on('click', 'a[data-pjax]', function(event) {
$.pjax.click(event, '#pjax-container')
})NOTE The new api gives you control over the delegated element container. $.fn.live always bound to document. This is what you still want to do most of the time.
$ git clone https://github.com/defunkt/jquery-pjax.git
$ cd jquery-pjax/
To run the test suite locally, start up the Sinatra test application.
$ ruby test/app.rb
== Sinatra/1.3.2 has taken the stage on 4567 for development with backup from WEBrick
$ open http://localhost:4567/
I was bitten by pjax’s built-in caching mechanism, and decided that caching should be out of scope for this sort of library. The browser does robust, well-understood caching. This fork removes pjax’s (imho-undesirable) caching mechanisms.
####Details
pjax snapshots and stores the html contents of the container on navigation. When hitting the back (or forward) button, pjax will restore the snapshotted html into the container.
The first problem is, bound events are not restored. I recognize that one can re-bind events on pjax:end, but that all depends on the those calls working on the snapshotted (not original) HTML. Chosen, for example, will not rebind events if it detects that it has run on the elements previously, so it simply stopped responding to mousedown after using the back button.
The second issue is that pjax has no real notion of cache policy or invalidation. You know what does? The browser. So I think caching is out of scope for this library. In my case, I set max-age and it works predictably.
Hope this helps, feedback welcome.