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.
So a user fills out a form then decides to click on a unrelated link that happens to be on the page say to a disclaimer page. Then using internal site navigation (not the browser back button) comes back to the form he was on. The link back is an ActionLink.
What is the best way to keep his data on the form. I figure I'll have to serialize the data and save it. I can do a ajax call before going to the other page. I'm looking for the sexy solution. Something that will handle it on a global scale.
Is this even a standard practice?
HTTP is Stateless. You are trying to bring some Stateful nature it !
If you really want to keep the data, You can keep in the Session variable and access it there. You need to override the click event and (in javascript) send the form data to an action via jQuery ajax post where you store it into Session. You can access it later when you come back to this page.
Do you really want to do that ? I think 80 % people knows that once they click on another link, the data will go away. You could probably show some alert message to ask "Are you sure to leave this page" like stackoverflow does.
1) I saw an interview question on this, and I'm assuming it's something to do with form submission and avoiding double submissions. Can someone confirm this?
2) Assuming this assumption is correct, can this be done with Ajax? If so is there a link someone can point me to?
(I'm assuming you'd generate some sort of random number and include it in the form as a hidden field, then ensure that number hadn't been submitted before for the session).
Redirect-after-post is a technique to avoid problems with the user refreshing or using the back button to get back to a posted form. In short, instead of providing a response page to an HTTP post, which will trigger another post if its reloaded, you issue a 303 redirect (or a 302, to support ancient browsers by taking advantage of a bug that is as old as the web). This causes the browser to issue a second HTTP request - a get this time - and if the response page to that is reloaded there shouldn't be any problems. Just make sure that all the changes are made by the post handler and the page you redirect to has no side effects.
If you post using XMLHttpRequest then the redirect will be followed; unless you specifically support it using the hash part of the location or the new HTML5 history methods then the back button and reload aren't going to trigger an AJAX post again.
My website uses ajax.
I've got a user list page which list users in an ajax table (with paging and more information stuff...).
The url of this page is :
/user-list
User list is created by ajax. When the user click on one user, he is redirected to a page which url is : /member/memberName
So we can see here that ajax is used to generate content and not to manage navigation (with the # character).
I want to detect bot to index all pages.
So, in ajax I want to display an ajax table with paging and cool ajax effetcs (more info...) and when I detect a bot I want to display all users (without paging) with a link to the member page like this :
JohnBob...
Do you think I can be black listed with this technique ? If you think so, could you please provide an alternative solution by keeping these clean urls and without redeveloping the user-list (without ajax) ?
Google support a specification to make AJAX crawlable:
http://code.google.com/web/ajaxcrawling/docs/specification.html
I did an experiment and it works:
http://seo-website-designer.com/SEO-Ajax-Google-Solution
As this is a Google specification, you won't get penalised (unless you abuse it).
Saying that, only Google support it at the moment (AFAIK).
Also, I believe following the concept of Progressive Enhancement is a better approach. That is, create a working html website then make the JavaScript enhance it
Maybe use the urls with an onclick to trigger your AJAX scripting? Like
Some URL
I don't think Google would punish you for this, you primarily use JScript, but you do provide a fall back for their bot, so your site doesn't get any less accessible.
EDIT
Ok, I misunderstood. Then my guess would be you basically have two options:
1. Write a different part of your site where bots end up, or,
2. Rewrite your current site to for example always give a 'full' page, with an option to only get, say, the content div. Then you can get only the content with JavaScript, but bots will always get a nice page.
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.
;)