I have a little work project I'm trying to solve. It involves automating data entry into a web-based database (ASP page). Part of the data entry requires clicking on a button to show a form. The button makes a call to WebForm_DoPostBackWithOptions(). I've been looking into trying to simulate the form POST using Javascript, but I am getting the impression it's a difficult thing to pull off, as I see that you need to supply the hidden VIEWSTATE data in the post, which just seems like a lot of work for little gain.
Anyway, I'm strictly limited to using IE 8, client-side scripting, and no external libs. There is no API or provision for automated access to the web database. The environment is totally Windows, and I do have .NET available. At this point, it seems the only viable option is to try to use a .NET WebBrowser object from javascript.
Are there any other ways of going about this?
Are you able to use xDomainRequests to post the data to the ASP page, and then handle it there? It's pretty much the same thing as ajax, except some versions of IE (8 included) don't support ajax.
There is a website that I visit often... let's call it www.example.com. And, I am able to interact with parts of this website. The interactions send XMLHttpRequest and get a response back through Javascript, jQuery I believe.
I'm not sure what technology will let me achieve what I want to do, and where to start. Basically, I want to add additional options/shortcuts that the site does not provide. I thought about maybe using a macro, but trying to use macro recording software is just a pain in the butt.
I inspected (using Google Chrome's Developer Tools) the XMLHttpRequest being sent back and forth and I noticed that it is simple JSON messages. I figured the best way to add enhancements to the site without waiting for the actual owners of the site to do so would be to simulate the website sending/recieving these XMLHttpRequest/Response and making additional adjustments to the DOM to provide extra shortcuts.
I don't want to interfere with the original site's functionality though... ie if I send a request and receive a response I want both the original script and my script to process the response. So, here is where I'm stuck... I'm not sure whether to go along the paths of creating a C# application or a Google Chrome extension (I use Google Chrome) or something else alltogether. Any pointers on what dev tools/languages will give me the ability to do what I want would be great. Thanks!
Chrome has built in support for user scripts. You can use these to modify the page as you see fit and also to make requests. Without more details regarding what exactly you want to do with these AJAX request it's hard to advise further.
I'm not 100% sure what your question is, but as I understand it, you want to be able to make changes to a certain website. If these changes can be done with js, i would recommend Greasemonkey for Firefox. It basically lets you run a custom script when you are visiting a certain webpage/domain. You can be as specific as you want about which pages use the script. Once your script loads jQuery, it is really easy to add any functionality.
https://addons.mozilla.org/en-US/firefox/addon/greasemonkey/
You can find pre-written scripts for tons of sites here:
http://userscripts.org/
Sadly I have to make a website (so to speak website) that can be placed on a CD.
My question is, can I use JavaScript and jQuery?
Some of the people who get the CD might have IE6 on Win XP installed.
Thank you.
Yes. jQuery explicitly supports IE6, and IE6 supports JavaScript (it would have to, otherwise jQuery couldn't support it) although it has some bugs.
You can put a website on to CD, and javascript/jquery should work fine. But beware that you'll only be able to have static resources: that is every request must be for a physical asset that exists on the CD. I.e you wont be able to have pages rendered dynamically in response to a request, and I'm pretty sure that you won't be able to make ajax requests too.
I had experience of making such a thing. It was a catalog of goods. So I grab all data and converted it to JSON. The catalog itself was only one page which show the goods using JS and client-side templating, doing some sorting and search. The biggest problem with using this catalog was that fact that reading much of small files from CD is really slow. So it was necessary to use as much CSS-sprites as possible instead of regular set of good's photos.
I'm trying to create a script to fill out a multi-page "form" that I have to fill out weekly (unemployment form actually), the 4th page ends up giving you a Checkbox and 2 Radio Buttons, all built by Javascript. When I navigate to this page using Mechanize I get html back without those 3 controls so I can't go any farther in the process.
Is this a common problem?
I'm filling out the form then just calling page = agent.submit(form, form.buttons.first) and it comes back without those controls built.
Mechanize is an HTML parser, not a JavaScript interpreter. If it's not in the HTML, there's nothing it can do. You need a "proper" browser. (By "proper" I mean one which can at least parse HTML, run JavaScript and ideally also interpret CSS.)
There are tools like Selenium & Co. that let you "remote-control" a "real" browser (Firefox, Internet Explorer, …) and there are efforts to build completely scriptable GUI-less browsers for precisely this use case.
Note: Depending on what country you are in, the unemployment agency may be in violation of anti-discrimination laws (especially if it's a government agency), so you could maybe force them to offer a JavaScript-free version of the form, but that's a) not a short-term solution and b) a topic for your lawyer, not StackOverflow.
Are the values of the generated form predictable? I often find it convenient to bypass all the individual form-helpers and just post to the form directly:
browser = Mechanize.new
browser.post(some_url, { field1 => val1, field2 => val2, ... })
You might want to look into using Watir if you're on Windows, or firewater on Mac/Linux or safariwatir on Mac only. All are basically the same code and are at the same site.
It's more oriented toward testing websites, but you can get at the content of the page using xpath, and from there proceed. Hopefully the browser will have processed the javascript for you and will return that. I've seen some browsers display the JS rendered HTML in their source view, and others don't, so I'm not sure what results you'll have.
As has been mentioned in other answers, you need to use something which drives a real web browser as there is currently no libraries capable of parsing that level of javascript (some can follow javascript redirects, but that is pretty much it). This would be ideal and easier to maintain.
If you really want to stick with the mechanize approach then you should simply be able to add the post field manually.
If they use a captcha to circumvent automated posting then you can need to resort to a simple decaptcha service (10 dollars for 2000 credits should be enough).
Lastly, it may be prudent to just not go through all this trouble.
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I'm building a web application with the Zend Framework. I have wanted to include some AJAX type forms and modal boxes, but I also want my application to be as accessible as possible. I want my application to be enhanced by AJAX, but also fully functional without AJAX.
So as a general guideline...when should I not use AJAX? I mean, should I bother making my application usable without AJAX? Or does everyone have AJAX enabled browsers these days?
If you mean "accessible" in the ADA sense, AJAX is usually a no-no - your site should provide all its content and core functionality using only standard (X)HTML and CSS. Any javascript used should merely extend the core functionality, and your site should be coded to work elegantly in the absence of a javascript-enabled browser.
Examples: if you want a user to click on a thumbnail and get a full-size version of the image as a result, you can make the thumbnail a link. Then, the onclick event will fire a JQuery method that cancels the navigation behavior of the link and pops up a JQuery floating div to show the image on the current page. If the user's browser doesn't support JavaScript, the onclick event will never fire, and the user will be presented the image in a new page. The core functionality is the same with or without scripting.
EDIT: Skeleton example, sans JQuery-specific code.
<html>
<body>
Some URL
</body>
</html>
To cancel the navigation operation, simply make sure that the method invoked by the onclick event returns false at the end.
A neat example of the JQuery image popup I described can be found here.
Use ajax if it adds value for the user.
If the ajax version adds a lot more value than the non-ajax version then it might justify the expense to develop a solution that caters for both clients. Generally i wouldn't recommend doing the extra work (remember.. more code results in more maintenance).
I think one point is missing here: Use Ajax only for content any search engine does not need to know.
98% of users will have AJAX enabled browsers.
A significant percentage of those people won't have it turned on when they first visit your site though (or at all, ever perhaps).
I've seen websites that look like a blank page without javascript on. Don't be one of them. Javascript to fix layout issues is a horrible idea in my opinion. Make sure it loads and looks ok without Javascript. If people can atleast see what they are missing out on, they are likely to switch it on, but if your website looks like it's just broken, then...
I often have noscript block Flash and JavaScript until I make the decision that your site is worthy.
So be sure to tell me what I'm missing if I have JavaScript turned off.
It depends on the complexity of your web application.
If you can, having it functional with javascript disabled is great, because it makes your application usable not only by users on js-disabled browsers but also by robots. The day you decide to write an application to automatically fill your forms, for example, you don't have to write an API from the ground up.
In any case, do not user AJAX for EVERYTHING! I have just inherited a project that basically consists of a single page that is populated by a ton of AJAX calls and I can tell that you just thinking about it gives me physical pain. I guess the original developer didn't like the concept of using the back/forward button in the browser as a mean of navigation.
Unless you are targeting mobile devices or other non-standard web users, you can be fairly sure that the vast majority has Javascript enabled, because most major sites (including SO) rely heavily on it.
I want my application to be as accessible as possible.
You can do things like rendering your modals and forms as a page that can operate standalone.
The AJAX version pulls the template into a modal/container, the standalone version checks if it's an AJAX request and renders the page including the header/footer (this can occur from the same URL if planned well)
The AJAX version intercepts the submit and does AJAX submission then provides an inline thank you, the non-AJAX opens a thank you page. Once again you can likely use the same pages for each of these functions if thought out correctly.
Reusing templates and URL's helps avoid additional maintenance for the AJAX/non-AJAX versions.
I want my application to be enhanced by AJAX, but also fully
functional without AJAX.
Thinking through the structure of your URLs and templates can go a long way towards this, if you make most of your AJAX requests pull in completely rendered templates (as opposed to just data) then you can usually use the same URL to serve both versions. You just serve only the guts of the modal/form to the AJAX request and the entire page to a regular request.
When should I not use AJAX?
You should not use AJAX if doing so will cause a poor experience for a significant portion of your user base (there are of course techniques that can be used to mitigate this)
You should not use AJAX if the development time associated with implementing it will be too significant to justify the improvements in user experience
You should not use AJAX for content which has significant SEO value without implementing an appropriate fallback that allows it to be indexed (Crawlers are improving constantly but it's still a good idea)
I mean, should I bother making my application usable without AJAX? Or
does everyone have AJAX enabled browsers these days?
I'd say a lot of the time it's unnecessary as the vast majority of users will have AJAX enabled browsers, but there are scenarios where it's critical such as SEO optimization or when a large portion of your user base is likely to use browsers that are less likely to support Javascript as well or where they're likely to have Javascript/AJAX disabled.
A few examples of these scenarios:
A website for a company or government that uses an outdated browser as standard
A website where a large portion of the users may be disabled in a manner that may negatively impact their experience such as a website for vision or motor-skill impaired people may be negatively impacted by updating content via AJAX especially if it occurs rapidly.
A site accessed regularly via a less common device or browser that will cause a negative impact to a large portion of users
So what should I do?
Think about who is going to be using the site, how they're going to access it, and what they're going to access it with. Also try to think about not just the present but also the future.
Design the site in a manner that will cater to the majority of these users.
Think who will gain and who will loose based on my decision to use AJAX and if in doubt have a look at your analytics data to help weigh up the decision and if you lack the data it may be worth updating your tracking and obtaining a sample to aid the decision
Think does my decision to use AJAX cause any contradictions with core requirements for this project
Use AJAX to enhance content where possible as opposed to making it mandatory ie the content should work with or without JS/AJAX
Consider the additional development time involved with the use of AJAX (if any)
My experience is, we should use ajax after it works without it. For a couple of reasons.
First, if something breaks in the ajax, and you don't have it working without it, the site simply doesn't work. For example, a product list with pagination. It should work with the links alone, then use ajax when possible.
Second, for site indexing and accessibility. If it works without ajax, it's better.
And it's easier to break something (even if only for a few moments). A bad piece of code, an uncaught exception, an external library not loaded, a blocking browser extension,...
After everything works without ajax, its quite easier to add ajax. Just have the ajax catch the action, add ajax=1 and when returning the result, return only what you need if ajax=1, otherwise return everything.
In the product list example, I would only return the products and pagination html, and add to the correct div. If ajax stops working, the whole page is loaded and the customer sees the second page as it loads.
Ajax adds a lot of value to UX. If done right, the user gets a great feel when using the site, and better data usage because it doesn't load the whole page everytime.
But the question being "when not to use ajax", I would say, you should always count on it to improve UX but not rely on it for the site to work (as other users also mentioned). And nowadays we need both, great code and great user experience.
My practice is to use two main pages, let's say index.py and ajax.py. First one is responsible for generating full website, and is default target of forms. Other one generates only output specific for adequate ajax query. Logic behind both of them is the same, only the method of generating output is a bit different.
In jquery I simply change action parameter when sending a request. It works both with and without ajax, although long time have I not seen someone with disabled js and ajax.
I like the thought of coding your application without JavaScript / Ajax and then adding it in later to enhance the UI without depriving users of functionality just because they don't have JavaScript enabled. I read about this in Pro ASP.NET MVC but I think I've seen it elsewhere in reading about unobtrusive JavaScript.
You should not make your service bloated with web 2.0 effects like accordion, modal/etc forms, image zoomers etc.
Use modern tech smarter (AJAX is one of them) and your users will be happy. Do not fear AJAX -- this is very good thing to make user expirience smooth. But don't do things because you like it - do them because your user need it ;)
When you want to make a website that looks like a website, not a fugly imitation of a desktop app?
You should not use AJAX or JavaScript in cases where:
your system needs to be accessible
your system needs to be search friendly
However, by using a modern JS framework with some solid "unobtrusive" practices, you can progressively enhance pages so that they remain accessible and search-friendly while offering a slick UI to users.
This totally depends on the type of application or feature you're developing. If it is crucial that the application is accessible despite the absence of Javascript, then it would help to have fallback methods (i.e. alternative forms) to allow your user to use said functionality/feature. For that, it will require you to invest some of your time developing methods for collecting information not just using client-side scripts but also on the server-side.
For miscellaneous features that only serves to enhance user experience, it's mostly not worth it to develop fallback methods.
There's no reason to totally not use AJAX. AJAX helps minimize your traffic after all.
You can if you wish always use AJAX and update the history state using Push State or for more compatibility use the hash with none HTML5 compliant browsers.
with this you can have your server load a page then javascript read the document.hash and resume the state of the application base on the state of the hash.
for example i got to /index.html i click into something for example a client to open the view client you can change the hash to #/view/client/{client_id}/ then if a reload or go back using the browser the hash with change and you can use the onhashchanged event to capture it and match the sites state to the new hash then same if a favorite a certain state
A couple of other scenarios where one may be better off NOT using AJAX:
Letting someone to log into the web application. Use traditional form submit instead.
Searching and returning more than a few 100 rows from the database. Either break the process down or let the server side language handle it.