All-in-one location/hashchange history management library - cross-browser

First of all, I know there's libraries that provide polyfills for location.pushState/popState (History.js, Hash.js, jQuery hashchange), so please don't just link to those.
I need a more powerful library to achieve the following in a RIA:
User clicks a link
library is notified and loads context via Ajax (no complete reload!)
All <a> elements are leveraged with a click handler that
prevents page reloads in 2. (preventDefault) and
calls location.pushState instead / sets location.hash for older browsers
loaded content is inserted in page and replaces current content
Continue with 1.
Also, previously loaded content should be restored as the user navigates back.
As an example, klick through Google+ in Internet Explorer <10 and any other browser.
Is there anything that comes even close? I need support for IE8, FF10, Safari 5 and Chrome 18. Also, it should have a permissive license like MIT or Apache.

I believe Sammy.js ( http://sammyjs.org) (MIT-licenced) has the best focus on what you want to do, with its 2 main pillars being:
Routes
Events
I could quote from the docs but it's pretty straightforward:
setup clientside routes that relate to stuff to be done, e.g: update the view through ajax
link events to call routes, e.g: call the route above when I click an link. (You would have to make sure e.preventDefault is called in the defined event I believe, since this is an app decision really, so that can't be abstracted away by any library that you're going to use imho)
Some relevant docs
http://sammyjs.org/docs
http://sammyjs.org/docs/routes
http://sammyjs.org/docs/events
Example for a route: (from http://sammyjs.org/docs/tutorials/json_store_1)
this.get('#/', function(context) {
$.ajax({
url: 'data/items.json',
dataType: 'json',
success: function(items) {
$.each(items, function(i, item) {
context.log(item.title, '-', item.artist);
});
}
});
});
Or something like
this.get('#/', function(context) {
context.app.swap(''); ///the 'swap' here indicates a cleaning of the view
//before partials are loaded, effectively rerendering the entire screen. NOt doing the swap enables you to do infinite-scrolling / appending style, etc.
// ...
});
Of course other clientside MVC-frameworks could be an option too, which take away even more plumbing, but might be overkill in this situation.
a pretty good (and still fairly recent) comparison:
http://codebrief.com/2012/01/the-top-10-javascript-mvc-frameworks-reviewed/
( I use Spine.js myself ) .
Lastly, I thought it might be useful to include an answer I've written a while ago that goes into detail to the whole best-practice (as I see it) in client-side refreshes, etc. Perhaps you find it useful:
Accessibility and all these JavaScript frameworks

I currently use PathJS in one of my applications.
It has been the best decision that i have made.
For your particular usecase take a look at HTML5 Example.
The piece of code that that makes the example work (from the source):
<script type="text/javascript">
// This example makes use of the jQuery library.
// You can use any methods as actions in PathJS. You can define them as I do below,
// assign them to variables, or use anonymous functions. The choice is yours.
function notFound(){
$("#output .content").html("404 Not Found");
$("#output .content").addClass("error");
}
function setPageBackground(){
$("#output .content").removeClass("error");
}
// Here we define our routes. You'll notice that I only define three routes, even
// though there are four links. Each route has an action assigned to it (via the
// `to` method, as well as an `enter` method. The `enter` method is called before
// the route is performed, which allows you to do any setup you need (changes classes,
// performing AJAX calls, adding animations, etc.
Path.map("/users").to(function(){
$("#output .content").html("Users");
}).enter(setPageBackground);
Path.map("/about").to(function(){
$("#output .content").html("About");
}).enter(setPageBackground);
Path.map("/contact").to(function(){
$("#output .content").html("Contact");
}).enter(setPageBackground);
// The `Path.rescue()` method takes a function as an argument, and will be called when
// a route is activated that you have not yet defined an action for. On this example
// page, you'll notice there is no defined route for the "Unicorns!?" link. Since no
// route is defined, it calls this method instead.
Path.rescue(notFound);
$(document).ready(function(){
// This line is used to start the HTML5 PathJS listener. This will modify the
// `window.onpopstate` method accordingly, check that HTML5 is supported, and
// fall back to hashtags if you tell it to. Calling it with no arguments will
// cause it to do nothing if HTML5 is not supported
Path.history.listen();
// If you would like it to gracefully fallback to Hashtags in the event that HTML5
// isn't supported, just pass `true` into the method.
// Path.history.listen(true);
$("a").click(function(event){
event.preventDefault();
// To make use of the HTML5 History API, you need to tell your click events to
// add to the history stack by calling the `Path.history.pushState` method. This
// method is analogous to the regular `window.history.pushState` method, but
// wraps calls to it around the PathJS dispatched. Conveniently, you'll still have
// access to any state data you assign to it as if you had manually set it via
// the standard methods.
Path.history.pushState({}, "", $(this).attr("href"));
});
});
</script>
PathJS has some of the most wanted features of a routing library:
Lightweight
Supports the HTML5 History API, the 'onhashchange' method, and graceful degredation
Supports root routes, rescue methods, paramaterized routes, optional route components (dynamic routes), and Aspect Oriented Programming
Well Tested (tests available in the ./tests directory)
Compatible with all major browsers (Tested on Firefox 3.6, Firefox 4.0, Firefox 5.0, Chrome 9, Opera 11, IE7, IE8, IE9)
Independant of all third party libraries, but plays nice with all of them
I found the last too points most attractive.
You can find them here
I hope you find this useful.

i'd like to suggest a combination of
crossroads.js as a router
http://millermedeiros.github.com/crossroads.js/
and hasher for handling browser history and hash urls (w/ plenty of fallback solutions):
https://github.com/millermedeiros/hasher/
(based on http://millermedeiros.github.com/js-signals/)
This will still require a few lines of code (to load ajax content etc.), but give you loads and loads of other possibilities when handling a route.
Here's an example using jQuery (none of the above libraries require jQuery, i'm just lazy...)
http://fiddle.jshell.net/Fe5Kz/2/show/light
HTML
<ul id="menu">
<li>
foo
</li>
<li>
bar/baz
</li>
</ul>
<div id="content"></div>
JS
//register routes
crossroads.addRoute('foo', function() {
$('#content').html('this could be ajax loaded content or whatever');
});
crossroads.addRoute('bar/{baz}', function(baz) {
//maybe do something with the parameter ...
//$('#content').load('ajax_url?baz='+baz, function(){
// $('#content').html('bar route called with parameter ' + baz);
//});
$('#content').html('bar route called with parameter ' + baz);
});
//setup hash handling
function parseHash(newHash, oldHash) {
crossroads.parse(newHash);
}
hasher.initialized.add(parseHash);
hasher.changed.add(parseHash);
hasher.init();
//add click listener to menu items
$('#menu li a').on('click', function(e) {
e.preventDefault();
$('#menu a').removeClass('active');
$(this).addClass('active');
hasher.setHash($(this).attr('href'));
});​

Have you looked at the BigShelf sample SPA (Single Page Application) from Microsoft? It sounds like it covers how to achieve most of what you're asking.
It makes use of History.js, a custom wrapper object to easily control navigation called NavHistory and Knockout.js for click handling.
Here's an extremely abbreviated workflow of how this works: first you'll need to initialize a NavHistory object which wraps history.js and registers a callback which executes when there is a push state or hash change:
var nav = new NavHistory({
params: { page: 1, filter: "all", ... etc ... },
onNavigate: function (navEntry) {
// Respond to the incoming sort/page/filter parameters
// by updating booksDataSource and re-querying the server
}
});
Next, you'll define one or more Knockout.js view models with commands that can be bound to links buttons, etc:
var ViewModel = function (nav) {
this.search = function () {
nav.navigate({ page: 2, filter: '', ... }); // JSON object matching the NavHistory params
};
}
Finally, in your markup, you'll use Knockout.js to bind your commands to various elements:
<a data-bind="click: search">...</a>
The linked resources are much more detailed in explaining how all of this works. Unfortunately, it's not a single framework like you're seeking, but you'd be surprised how easy it is to get this working.
One more thing, following the BigShelf example, the site I'm building is fully cross-browser compatible, IE6+, Firefox, Safari (mobile and desktop) and Chrome (mobile and desktop).

The AjaxTCR Library seems to cover all bases and contains robust methods that I haven't seen before. It's released under a BSD License (Open Source Initiative).
For example, here are five AjaxTCR.history(); methods:
init(onStateChangeCallback, initState);
addToHistory(id, data, title, url, options);
getAll();
getPosition();
enableBackGuard(message, immediate);
The above addToHistory(); has enough parameters to allow for deep hash-linking in websites.
More eye-candy of .com.cookie(), .storage(), and .template() provides more than enough methods to handle any session data requirements.
The well documented AjaxTCR API webpage has a plethora of information with downloadable doc's to boot!
Status Update:
That website also has an Examples Webpage Section including downloadable .zip files with ready to use Front End(Client) and Back End(Server) project files.
Notably are the following ready-to-use examples:
One-way Cookie
HttpOnly Cookies
History Stealing
History Explorer
There are quite a bit other examples that rounds out the process to use many of their API methods, making any small learning curve faster to complete.

Several suggestions
ExtJs, see their History Example, and here are the docs.
YUI Browser History Manager.
jQuery BBQ seem to provide a more advanced feature-set over jQuery.hashcode.
ReallySimpleHistory may also be of help, though it's quite old and possibly outdated.
Note: ExtJs History has been extended to optimize duplicate (redundant) calls to add().

PJAX is the process you're describing.
The more advanced pjax techniques will even start to preload the content, when the user hovers over the link.
This is a good pjax library.
https://github.com/MoOx/pjax
You mark the containers which need will be updated on the subsequent requests:
new Pjax({ selectors: ["title", ".my-Header", ".my-Content", ".my-Sidebar"] })
So in the above, only the title, the .my-header, .my-content, and .my-sidebar will be replaced with the content from the ajax call.
Somethings to look out for
Pay attention to how your JS loads and detects when the page is ready. The javascript will not reload on new pages. Also pay attention to when any analytics calls get called, for the same reason.

Related

Message between multi-level elements (Polymer)

What's the best way to change data between different levels (in DOM) elements?
For example, I would like to save an REST service base URL in a variable on index.html (<template is="auto-binding"), so I could access this value from anywhere in the project, regardless of the hierarchy.
I guess <core-storage> would be an option, is it? What are the other options?
Thanks
Edit:
Just found my answer here: https://stackoverflow.com/a/24876397/2750721
As Trevor Dixon explained in an earlier answer you can use globals. Divshot does this for a lot of their apps (even before it was officially in the docs) but they use their own custom element for globals.
So far their is no silver bullet answer though. My experience so far is it depends on the situation as far as what is the best practice. Here are some generalizations I usually think about...
Global browser storage (<core-storage>, <local-forage>, pouchDB, IndexedDB, cookies, etc.)
Usage: this is great if you have data that you need to share with multiple elements, managing offline data, and for maintaining state/data across apps that utilize traditional browser page navigation
Considerations: can have limited space on client (localStorage has 5mb base as an example), usually synchronous API's (not for all though like Mozilla's localForage), limited to a single browser, can get complicated fast in maintaining state
Custom Events
Usage: great for to sharing small amounts of data and signaling across the application. Events are clean & bubble up throughout the DOM, ignoring shadow boundaries
Considerations: not good for large amounts of data, not optimal for Virtual DOM approaches, reliable & easy to use, limited to window & document lifecycle (refresh will not maintain data state)
Globals
Usage: Great for sharing small & large amounts of data across the app in JavaScript objects
Considerations: Maintenance & performance could issues if not tended to early on, Polymer has a built in mechanism for globals so it is easy to use, bound to the document & window lifecycle
Generally, no you'll use a combination of these strategies with a restful API that data is ultimately persisted to and synchronized with. this is not always the case but it is typical in modern JavaScript applications on the client.
I'd do something like what is suggested in the Polymer docs under "Supporting global variables". https://www.polymer-project.org/0.5/docs/polymer/polymer.html#global. Make an element that uses a function closure to share state between all instances of the element, then create an instance of that element any time you need access to the shared data.
Copied straight from the docs:
<polymer-element name="app-globals">
<script>
(function() {
// these variables are shared by all instances of app-globals
var firstName = 'John';
var lastName = 'Smith';
Polymer({
ready: function() {
// copy global values into instance properties
this.firstName = firstName;
this.lastName = lastName;
}
});
})();
</script>
</polymer-element>
Then use the element as you would any other. You can
access its properties using Polymer data binding or plain JavaScript:
<polymer-element name="my-component">
<template>
<app-globals id="globals"></app-globals>
<div id="firstname">{{$.globals.firstName}}</div>
<div id="lastname">{{$.globals.lastName}}</div>
</template>
<script>
Polymer({
ready: function() {
console.log('Last name: ' + this.$.globals.lastName);
}
});
</script>
</polymer-element>
You can use custom events to alert changes between multi-level element, e.g.
<component-1>
Polymer({
ready: function() {
this.addEventListener("data-change", function(e) {
this.data = e.detail.data;
});
},
</component-1>
<component-deep>
Polymer({
dataChanged: function() {
this.fire("data-change", {data: this.data});
}
});
</component-deep>

How to execute a script in chrome extension? when the content is changed?

I want to execute a chrome script,when the content of webpage is update (E.g like Facebook)
So what method I should use for that?
You can use
$("body").bind("DOMSubtreeModified", function() {
alert("something changed");
});
Note: DOMSubtreeModified is deprecated
You should try it with chrome.* API:
chrome.tabs.onUpdated.addListener(
function(integer tabId, object changeInfo, Tab tab) {
//your code
});
See here for documentation:
http://code.google.com/chrome/extensions/tabs.html#event-onUpdated
It should work for updates like (AJAX) requests etc...
As sachleen said, you can use DOMSubtreeModified listener
document.addEventListener("DOMSubtreeModified", methodToRun);
Note that the Mutation Events are performance hogs which can't really be tamed well (they fire too often and slow down the page a lot). Therefore, they have been deprecated over a year ago and should be used only when really needed. However, they work.
If you want this for a Chrome extension, you could use the new and shiny Mutation Observers from DOM Level 4 (follow the links there, they explain a lot!). Where DOMSubtreeModified fired a thousand times, MutationObserver fires only once with all the modifications contained and accessible.
Works for (as of 2012/06):
Chrome 18+ (prefixed, window.WebKitMutationObserver)
Firefox 14+ (unprefixed)
WebKit nightlies

Implementation of History.js

I am trying to implement History.js for my ajax site so that I can use forward and back buttons and even bookmarks. However the example # https://github.com/browserstate/History.js/ has me a bit confused as into how to implement it. Does anyone have a simple tutorial or example on how to use this. An example we can use to start the example is a navigation link such as
<script type="text/javascript">
window.onload = function()
{
function1();
};
<ul>
<li>Function1</li>
<li><a href="javascript:function2('param', 'param')"</a></li>
</ul>
I had trouble fully understanding how to use History.js. Here is some code from their wiki with my comments for explanation:
1. Get a reference to the history.js object
To get a reference to the History.js object reference window.History (Capitol 'H').
var History = window.History;
To check if HTML5 history is enabled check History.enabled. History.js will still work using hash tags if it is not.
History.enabled
2. Listen for history changes and update your view from here
To listen for history state changes bind to the statechange event of the Adapter object.
History.Adapter.bind(window,'statechange',function(){
var State = History.getState();
History.log(State.data, State.title, State.url);
});
3. Manipulate history states by using push or replace
To add a state to the history, call pushState. This will add a state to the end of the history stack which will trigger the 'statechange' event as shown above.
History.pushState({data:"any kind of data object"}, "State Title", "?urlforthestate=1");
To replace a state to the history, call replaceState. This will replace the last state in the history stack which will trigger the 'statechange' event as shown above.
History.replaceState({data:"any kind of data object"}, "State Title", "?urlforthestate=1");
The difference between pushState and replaceState is that pushState will add a state to the history list, replaceState will overwrite the last state.
NOTE: pushState and replaceState serialize the data object, so use minimal data there.
4. If you want to add additional ui for the user to be able to navigate the history, use the navigation commands
Use back and go to navigate the history via code.
History.back();
History.go(2);
Additional: Using "a" tags with history
To use "a" tags with history you will need to intercept click events and prevent the browser from navigating by using the event.preventDefault() method.
Example:
Dogs and Cats
$('a')​.click(function(e){
e.preventDefault();
var url = $(this).attr('href');
var title = $(this).attr('title');
History.pushState({data:title}, title, url);
})​;
I hope this helps.
Refer this question: Implementing "Back button" on jquery ajax calls
Some more info related to RSH
How to implement RSH (Really Simple History) for Ajax History Back Button

How to extend a native mootools method

Is it possible to extend the addEvent function in mootools to do something and also calls the normal addEvent method? Or if someone has a better way to do what I need I'm all years.
I have different 'click' handlers depending on which page I'm on the site. Also, there might be more than one on each page. I want to have every click on the page execute a piece of code, besides doing whatever that click listener will do. Adding that two lines on each of the handlers, would be a PITA to say the least, so I thought about overriding the addEvent that every time I add a 'click' listener it will create a new function executing the code and then calling the function.
Any idea how I could do it?
Whereas this is not impossible, it's a questionable practice--changing mootools internal apis. Unless you are well versed with mootools and follow dev direction on github and know your change won't break future compatibility, I would recommend against it.
The way I see it, you have two routes:
make a new Element method via implement that does your logic. eg: Element.addMyEvent that does your thing, then calls the normal element.addEvent after. this is preferable and has no real adverse effects (see above)
change the prototype directly. means you don't get to refactor any code and it will just work. this can mean others that get to work with your code will have difficulties following it as well as difficulties tracing/troubleshooting- think, somebody who knows mootools and the standard addEvent behaviour won't even think to check the prototypes if they get problems.
mootools 2.0 coming will likely INVALIDATE method 2 above if mootools moves away from Element.prototype modification in favour of a wrapper (for compatibility with other frameworks). Go back to method 1 :)
I think solution 1 is better and obvious.
as for 2: http://jsfiddle.net/dimitar/aTukP/
(function() {
// setup a proxy via the Element prototype.
var oldProto = Element.prototype.addEvent;
// you really need [Element, Document, Window] but this is fine.
Element.prototype.addEvent = function(type, fn, internal){
console.log("added " + type, this); // add new logic here. 'this' == element.
oldProto.apply(this, arguments);
};
})();
document.id("foo").addEvent("click", function(e) {
e.stop();
console.log("clicked");
console.log(e);
});
it is that simple. keep in mind Element.events also should go to document and window. also, this won't change the Events class mixin, for that you need to refactor Events.addEvent instead.

How do I access the popup page DOM from bg page in Chrome extension?

In Google Chrome's extension developer section, it says
The HTML pages inside an extension
have complete access to each other's
DOMs, and they can invoke functions on
each other. ... The popup's contents
are a web page defined by an HTML file
(popup.html). The popup doesn't need
to duplicate code that's in the
background page (background.html)
because the popup can invoke functions
on the background page
I've loaded and tested jQuery, and can access DOM elements in background.html with jQuery, but I cannot figure out how to get access to DOM elements in popup.html from background.html.
can you discuss why you would want to do that? A background page is a page that lives forever for the life time of your extension. While the popup page only lives when you click on the popup.
In my opinion, it should be refactored the other way around, your popup should request something from the background page. You just do this in the popup to access the background page:
chrome.extension.getBackgroundPage()
But if you insist, you can use simple communication with extension pages with sendRequest() and onRequest. Perhaps you can use chrome.extension.getViews
I understand why you want to do this as I have run into the problem myself.
The easiest thing I could think of was using Google's method of a callback - the sendRequest and onRequest methods work as well, but I find them to be clunky and less straightforward.
Popup.js
chrome.extension.getBackgroundPage().doMethod(function(params)
{
// Work with modified params
// Use local variables
});
Background.html
function doMethod(callback)
{
if(callback)
{
// Create/modify params if needed
var params;
// Invoke the callback
callback(params);
}
}
As other answers mention, you can call background.js functions from popup.js like so:
var _background = chrome.extension.getBackgroundPage();
_background.backgroundJsFunction();
But to access popup.js or popup.html from background.js, you're supposed to use the messages architecture like so:
// in background.js
chrome.runtime.sendMessage( { property: value } );
// in popup.js
chrome.runtime.onMessage.addListener(handleBackgroundMessages);
function handleBackgroundMessages(message)
{
if (message.property === value)
// do stuff
}
However, it seems that you can synchronously access popup.js from background.js, just like you can synchronously access the other way around. chrome.extension.getViews can get you the popup window object, and you can use that to call functions, access variables, and access the DOM.
var _popup = chrome.extension.getViews( { type: 'popup' } )[0];
_popup.popupJsFunction();
_popup.document.getElementById('element');
_popup.document.title = 'poop'
Note that getViews() will return [] if the popup is not open, so you have to handle that.
I'm not sure why no one else mentioned this. Perhaps there's some pitfalls or bad practices to this that I've overlooked? But in my limited testing in my own extension, it seems to work.