I'm taking an online course from a site that does not provide for asking questions about the content, so I am asking you.
This is one of the MUSTS for page titles:
"On a so-called single-page application — in which AJAX is used to bring in new content without refreshing or loading the entire web page — any time that the URL changes, the page title should be updated accordingly"
I always thought that if you used ajax to change part of a page the page itself would remain static. That is why would a URL change with an AJAX call. Are there any examples showing what this looks like?
AJAX requests don’t change the browser URL or history. To mimic the behaviour of traditional websites, single page apps will modify the URL and history and use the URL to change the view.
For more on changing the browser history, see Adding and modifying History entries.
I have read articles that give various ways to do "URL masking" so that the browser's URL bar does not show the actual location of the content. Such methods include setting up an .htaccess file, showing content in an iframe, or loading content from another source with javascript.
The problem with all of these methods is that the URL shown in the browser can actually be used to view the content I want to protect, even though it's coming from another location.
I need a way to have the browser display protected content while the URL bar displays a URL that will NOT show that content, because I don't want a person who has been given access to the content to be able to share access to that content by giving the URL away to others.
Is this possible?
Maybe you could use something like a randomly re-generated URI. Every time the link is consumed through an authorized channel, the route is invalidated on the server, and a new one takes its place.
Note:
The safest way to prevent unauthorized access to a URL may be to add authentication (user/pass or otherwise) to your content.
This question exists in different flavors, but not for AJAX pages.
I use AJAX to pull a single video into my page and I want a custom FB share button for it. Everything I've read so far says that FB pulls the required title and image from meta-tags in the page's < head> section (og:image and og:title).
I've tried to change the meta properties when the AJAX call returns, before rendering the share button. This hasn't worked. It uses the values that were present upon initial page load. I have yet to encounter a single answer to this question.
Are there data attributes I can add to the 'fb-like' div to specify a custom title and image (similar to data-href)?
Danke!
You need an individual URL for each individual piece of content that you want to share. Open Graph objects (and simple shared links “become” such, automatically) are identified by their URL (og:url).
Now if your whole page is built on AJAX, you still need to create such individual URLs somehow – the Facebook scraper tool does not “speak” JavaScript, and relies solely on the OG meta information that the server delivers for any URL it requests.
Since the hash part of an URL is only of relevance client-side (and does not even get send to the server), “typical” AJAX URLs that rely on those to tell the client which piece of content to load in the background are no good here.
So if you want to share two pieces of content (videos) as http://www.example.com/?v=vid1 and http://www.example.com/?v=vid2, then you have to make sure that your server delivers the meta data for each video under its respective URL.
I have a site that I want to load links in the centre column, so why would I use AJAX over an iframe?
AJAX is a system which allows you to get data - any data - from a server. This is in contrast to iframes which simply load in a HTML document or fragment based on a given URL.
THe strength of AJAX's flexibility over iframes is their ability to give you back raw data with which you then use to build or update your view. Consider this example: you have a dataset that needs to be displayed in tabular form, so you could set up a page that contains the table with your data in it and load that in via iframe.
A better option however, is to get the raw data from the server with AJAX and send it to your application uncluttered by markup and extra tags. Your page then builds the table in whatever part of the page it needs, according to how your application needs it to appear right at that point.
Where iframes can load HTML content that must be presented as it is built, AJAX allows the developer to separate the data from the way it is presented, giving them the freedom to manipulate it as much as they like and use it in as many ways, pages and applications as they need.
More Information
AJAX allows the client or web page to send data back to the server to do things with (such as changing passwords, updating settings, or transaction processing, etc.) so if your page or application needs two-way communication without refreshing the page, AJAX is probably the technology you'd use.
Also, using iframes restricts your ability to work with the data inside. An iframe creates a new context which you can think of as a container of sorts - the data inside is safe from the outside and vice versa. This often means your CSS won't flow down into your iframe giving you unexpected results. On some browsers, clicking a link in an iframe can actually cause the link's destination to load inside the iframe instead of changing the whole page - usually not what you want.
I'm writing an AJAX app, but as the user moves through the app, I'd like the URL in the address bar to update despite the lack of page reloads. Basically, I'd like for them to be able to bookmark at any point and thereby return to the current state.
How are people handling maintaining RESTfulness in AJAX apps?
The way to do this is to manipulate location.hash when AJAX updates result in a state change that you'd like to have a discrete URL. For example, if your page's url is:
http://example.com/
If a client side function executed this code:
// AJAX code to display the "foo" state goes here.
location.hash = 'foo';
Then, the URL displayed in the browser would be updated to:
http://example.com/#foo
This allows users to bookmark the "foo" state of the page, and use the browser history to navigate between states.
With this mechanism in place, you'll then need to parse out the hash portion of the URL on the client side using JavaScript to create and display the appropriate initial state, as fragment identifiers (the part after the #) are not sent to the server.
Ben Alman's hashchange plugin makes the latter a breeze if you're using jQuery.
Look at sites like book.cakephp.org. This site changes the URL without using the hash and use AJAX. I'm not sure how it does it exactly but I've been trying to figure it out. If anyone knows, let me know.
Also github.com when looking at a navigating within a certain project.
It is unlikely the writer wants to reload or redirect his visitor when using Ajax.
But why not use HTML5's pushState/replaceState?
You'll be able to modify the addressbar as much as you like. Get natural looking urls, with AJAX.
Check out the code on my latest project:
http://iesus.se/
This is similar to what Kevin said. You can have your client state as some javascript object, and when you want to save the state, you serialize the object (using JSON and base64 encoding). You can then set the fragment of the href to this string.
var encodedState = base64(json(state));
var newLocation = oldLocationWithoutFragment + "#" + encodedState;
document.location = newLocation; // adds new entry in browser history
document.location.replace(newLocation); // replaces current entry in browser history
The first way will treat the new state as a new location (so the back button will take them to the previous location). The latter does not.
SWFAddress works in Flash & Javascript projects and lets you create bookmarkable URLs (using the hash method mentioned above) as well as giving you back-button support.
http://www.asual.com/swfaddress/
The window.location.hash method is the preferred way of doing things. For an explanation of how to do it,
Ajax Patterns - Unique URLs.
YUI has an implementation of this pattern as a module, which includes IE specific work arounds for getting the back button working along with re-writing the address using the hash. YUI Browser History Manager.
Other frameworks have similar implementations as well. The important point is if you want the history to work along with the re-writing the address, the different browsers need different ways of handling it. (This is detailed in the first link article.)
IE needs an iframe based hack, where Firefox will produce double history using the same method.
If OP or others are still looking for a way to do modify browser history to enable state, using pushState and replaceState, as suggested by IESUS, is the 'right' way to do it now. It's main advantage over location.hash seems to be that it creates actual URLs, not just hashes. If browser history using hashes is saved, and then revisited with JavaScript disabled, the app won't work, since the hashes aren't sent to the server. However, if pushState has been used, the entire route will be sent to the server, which you can then build to respond appropriately to the routes. I saw an example where the same mustache templates were used on both the server and the client side. If the client had JavaScript enabled, he would get snappy responses by avoiding the roundtrip to the server, but the app would work perfectly fine without the JavaScript. Thus, the app can gracefully degrade in the absence of JavaScript.
Also, I believe there is some framework out there, with a name like history.js. For browsers that support HTML5, it uses pushState, but if the browser doesn't support that, it automatically falls back to using hashes.
Check if user is 'in' the page, when you click on the URL bar, JavaScript says you are out of page.
If you change the URL bar and press 'ENTER' with the symbol '#' within it then you go into the page again, without click on the page manually with mouse cursor, then a keyboard event command (document.onkeypress) from JavaScript will be able to check if it's enter and active the JavaScript for redirection.
You can check if user is IN the page with window.onfocus and check if he's out with window.onblur.
Yeah, it's possible.
;)