I inherited a large framework (my employer purchased a product) that uses ASP.Net modules (.ascx files loaded dynamically by Default.aspx). The product did not, of course, come with its tests (at least, I assume the product has tests).
Because the ASP.Net postback client-side experience is awful, I've started adding more modern, Javascript-heavy functionality both to the existing modules, and in the new ones I create. Due to how the system works I really cannot move away from the module-driven framework currently in place into an MVC setup.
I'm looking for a test framework that can access both the browser and the back-end framework. I think I've come up with a set of requirements for this framework/combination of frameworks:
MUST handle navigation to multiple pages (wizard-like behavior).
MUST handle new window popups.
MUST handle DOM manipulation via Javascript (showing/hiding elements).
MUST emulate mouse/keyboard input on pages.
MUST be able to query/validate Javascript variable states.
MUST be able to query/validate back-end SQL Server.
MAY be able to query/validate back-end ASP.Net state. (Nice to have.)
Ideally it would have integration with VS's Test Explorer, but that's not a hard-and-fast requirement.
Does such a framework exist? The google searching I've done has come up with plenty for single-page Javascript-driven sites, MVC sites, and plain ASP.Net sites without pretty Javascript, but I've had a hard time finding (or recognizing) a framework to fit my needs.
One of the design proposed for a web application I am working on suggests using javascript to generate all html content. Basically to create a page in the application you would use a homemade javascript framework to build the dynamic html on the page. The pages of this webpage are very complex and all of the html markup would be generated via javascript using our custom built framework. The framework would essentially need a method to create each element on the page you wanted to produce.
What are some of the pros and cons of this approach?
The biggest cons of it are that you must rely on the end user's client browser to correctly render all of your content. An out of date browser or an untested browser is likely to result in broken content or no content. This is distinct from and more severe than the problems those same browsers encounter with HTML & CSS they cannot correctly render. If the markup is supplied to the browser, it may incorrectly render the CSS, but at least the content will be accessible. Using a script to generate all the markup can easily result in no markup being generated.
Then there are the users who run without JavaScript, or with something like NoScript blocking most scripts. They'll not see any of your content either. Thirdly, your content will not be indexed by most search engines.
Addendum
Relating to developer skill sets, working strictly from a JavaScript framework could tromp on the web development division of labor somewhat, if you have such a division. Unless the framework is able to maintain a good separation between the generation of markup, CSS, & application script, your programmers may find themselves more deeply in the role of designer and content editor than they are accustomed to (if you have a division of labor between those aspects of development).
From the comments below, we learn that this is intended for an intranet application in a controlled browser environment. This moots the end-user testing issues mentioned above to some degree, but there is always a danger of a browser upgrade breaking application code in JavaScript.
I cannot think of any positive outcomes that would outweight the potential negative outcomes (by my own judgement, anyway)
The strategy adopted by serious web sites is to start with basic HTML, then add CSS to tidy the layout, then add script to make the users' life easier by enhancing functionality (and not to add time wasting and annoying animations). That way you always have a fallback if something doesn't work or scripting fails for some reason. I deliberately left out the "add annoying advertisements" since they aren't part of the functional design.
To design the site, you should start by determining what it is that your web site is supposed to do (i.e. the vision). Then set out some goals that achieve that vision. Then chose the most efficient design to deliver on the goals—at this point you should not have yet decided on the implementation technology.
Then choose the most appropriate technology and design based on reliability, maintainability, longevity and supportability. That will lead you to a detailed design and implementation.
If, after all that, the best option is a 100% scripted client, so be it. But the fact that very, very few web sites have chosen that architecture makes me very much doubt that it'll be the winner.
When a developing a web app, versus a web site, what reasons are there to use multiple HTML pages, rather than using one html page and doing everything through Javascript?
I would expect that it depends on the application -- maybe -- but would appreciate any thoughts on the subject.
Thanks in advance.
EDIT:
Based on the responses here, and some of my own research, if you wanted to do a single-page, fully JS-Powered site, some useful tools would seem to include:
JQuery Plug Ins:
JQuery History:
http://balupton.com/projects/jquery-history
JQuery Address:
http://plugins.jquery.com/project/jquery-address
JQuery Pagination:
http://plugins.jquery.com/project/pagination
Frameworks:
Sproutcore
http://www.sproutcore.com/
Cappucino
http://cappuccino.org/
Possibly, JMVC:
http://www.javascriptmvc.com/
page based applications provide:
ability to work on any browser or device
simpler programming model
they also provide the following (although these are solvable by many js frameworks):
bookmarkability
browser history
refresh or F5 to repeat action
indexability (in case the application is public and open)
One of the bigger reasons is going to be how searchable your website is.
Doing everything in javascript is going to make it complicated for search engines to crawl all content of your website, and thus not fully indexing it. There are ways around this (with Google's recent AJAX SEO guidelines) but I'm not sure if all search engines support this yet. On top of that, it's a little bit more complex then just making separate pages.
The bigger issue, whether you decide to build multiple HTML pages, or you decide to use some sort of framework or CMS to generate them for you, is that the different sections of your website have URL's that are unique to them. E.g., an about section would have a URL like mywebsite.com/about, and that URL is used on the actual "about" link within the website.
One of the biggest downfalls of single-page, Ajax-ified websites is complexity. What might otherwise be spread across several pages suddenly finds its way into one huge, master page. Also, it can be difficult to coordinate the state of the page (for example, tracking if you are in Edit mode, or Preview mode, etc.) and adjusting the interface to match.
Also, one master page that is heavy on JS can be a performance drag if it has to load multiple, big JS files.
At the OP's request, I'm going to discuss my experience with JS-only sites. I've written four relevant sites: two JS-heavy (Slide and SpeedDate) and two JS-only (Yazooli and GameCrush). Keep in mind that I'm a JS-only-site bigot, so you're basically reading John Hinkley on the subject of Jody Foster.
The idea really works. It produces gracefully, responsive sites at very low operational costs. My estimate is that the cost for bandwidth, CPU, and such goes to 10% of the cost of running a similar page-based site.
You need fewer but better (or at least, better-trained) programmers. JavaScript is an powerful and elegant language, but it has huge problems that a more rigid and unimaginative language like Java doesn't have. If you have a whole bunch of basically mediocre guys working for you, consider JSP or Ruby instead of JS-only. If you are required to use PHP, just shoot yourself.
You have to keep basic session state in the anchor tag. Users simply expect that the URL represents the state of the site: reload, bookmark, back, forward. jQuery's Address plug-in will do a lot of the work for you.
If SEO is an issue for you, investigate Google Ajax Crawling. Basically, you make a very simple parallel site, just for search engines.
When would I not use JS-only? If I were producing a site that was almost entirely content, where the user did nothing but navigate from one place to another, never interacting with the site in a complicated manner. So, Wikipedia and ... well, that's about it. A big reference site, with a lot of data for the user to read.
modularization.
multiple files allows you to mre cleanly break out different workflow paths and process parts.
chances are your Business Rules are something that do not usually directly impact your layout rules and multiple files would better help in editing on what needs to be edited without the risk of breaking something unrelated.
I actually just developed my first application using only one page.
..it got messy
My idea was to create an application that mimicked the desktop environment as much as possible. In particular I wanted a detailed view of some app data to be in a popup window that would maintain it's state regardless of the section of the application they were in.
Thus my frankenstein was born.
What ended up happening due to budget/time constraints was the code got out of hand. The various sections of my JavaScript source got muddled together. Maintaining the proper state of various views I had proved to be... difficult.
With proper planning and technique I think the 'one-page' approach is a very easy way to open up some very interesting possibilities (ex: widgets that maintain state across application sections). But it also opens up many... many potential problem areas. including...
Flooding the global namespace (if you don't already have your own... make one)
Code organization can easily get... out of hand
Context - It's very easy to
I'm sure there are more...
In short, I would urge you to stay away from relying on JavaScript dependency for the compatibility issue's alone. What I've come to realize is there is simply no need rely on JavaScript to everything.
I'm actually in the process of removing JavaScript dependencies in loo of Progressive Enhancement. It just makes more sense. You can achieve the same or similar effects with properly coded JavaScript.
The idea is too...
Develop out well-formatted, fully functional application w/o any JavaScript
Style it
Wrap the whole thing with JavaScript
Using Progressive Enhancement one can develop an application that delivers the best possible experience for the user that is possible.
For some additional arguments, check out The Single Page Interface Manifesto and some (mostly) negative reaction to it on Hacker News (link at the bottom of the SPI page):
The Single Page Interface Manifesto: http://itsnat.sourceforge.net/php/spim/spi_manifesto_en.php
stofac, first of all, thanks for the link to the Single Page Interface (SPI) Manifesto (I'm the author of this boring text)
Said this, SPI != doing everything through Javascript
Take a look to this example (server-centric):
http://www.innowhere.com/insites/
The same in GAE:
http://itsnatsites.appspot.com/
More info about the GAE approach:
http://www.theserverside.com/news/thread.tss?thread_id=60270
In my opinion coding a complex SPI application/web site fully on JavaScript is very very complex and problematic, the best approach in my opinion is "hybrid programming" for SPI, a mix of server-centric for big state management and client-centric (a.k.a JavaScript by hand) for special effects.
Doing everything on a single page using ajax everywhere would break the browser's history/back button functionality and be annoying to the user.
I utterly despise JS-only sites where it is not needed. That extra condition makes all the difference. By way of example consider the oft quoted Google Docs, in this case it not only helps improve experiences it is essential. But some parts of Google Help have been JS-only and yet it adds nothing to the experience, it is only showing static content.
Here are reasons for my upset:
Like many, I am a user of NoScript and love it. Pages load faster, I feel safer and the more distracting adverts are avoided. The last point may seem like a bad thing for webmasters but I don't want anyone to get rewarded for pushing annoying flashy things in my face, if tactless advertisers go out of business I consider it natural selection.
Obviously this means some visitors to your site are either going to be turned away or feel hassled by the need to provide a temporary exclusion. This reduces your audience.
You are duplicating effort. The browser already has a perfectly good history function and you shouldn't need to reinvent the wheel by redrawing the previous page when a back button is clicked. To make matters worse going back a page shouldn't require re-rendering. I guess I am a student of If-it-ain't-broke-don't-fix-it School (from Don't-Repeat-Yourself U.).
There are no HTTP headers when traversing "pages" in JS. This means no cache controls, no expiries, content cannot be adjusted for requested language nor location, no meaningful "page not found" nor "unavailable" responses. You could write error handling routines within your uber-page that respond to failed AJAX fetches but that is more complexity and reinvention, it is redundant.
No caching is a big deal for me, without it proxies cannot work efficiently and caching has the greatest of all load reducing effects. Again, you could mimic some caching in your JS app but that is yet more complexity and redundancy, higher memory usage and poorer user experience overall.
Initial load times are greater. By loading so much Javascript on the first visit you are causing a longer delay.
More JavaScript complexity means more debugging in various browsers. Server-side processing means debugging only once.
Unfuddle (a bug-tracker) left a bad taste. One of my most unpleasant web experiences was being forced to use this service by an employer. On the surface it seems well suited; the JS-heavy section is private so doesn't need to worry about search engines, only repeat visitors will be using it so have time to turn off protections and shouldn't mind the initial JS library load.
But it's use of JS is pointless, most content is static. "Pages" were still being fetched (via AJAX) so the delay is the same. With the benefit of AJAX it should be polling in the background to check for changes but I wouldn't get notified when the visible page had been modified. Sections had different styles so there was an awkward re-rendering when traversing those, loading external stylesheets by Javascript is Bad Practice™. Ease of use was sacrificed for whizz-bang "look at our Web 2.0" features. Such a business-orientated application should concentrate on speed of retrieval, but it ended up slower.
Eventually I had to refuse to use it as it was disrupting the team's work flow. This is not good for client-vendor relationships.
Dynamic pages are harder to save for offline use. Some mobile users like to download in advance and turn off their connection to save power and data usage.
Dynamic pages are harder for screen readers to parse. While the number of blind users are probably less than those with NoScript or a mobile connection it is inexcusable to ignore accessibility - and in some countries even illegal, see the "Disability Discrimination Act" (1999) and "Equality Act" (2010).
As mentioned in other answers the "Progressive Enhancement", née "Unobtrusive Javascript", is the better approach. When I am required to make a JS-only site (remember, I don't object to it on principle and there are times when it is valid) I look forward to implementing the aforementioned AJAX crawling and hope it becomes more standardised in future.
I would like to know, how powerful/viable are JavaScript only clients based on say, GWT/gxt/vaadin, when compared to DHTML clients such as those made with wicket, tapestry, click etc?
My boss has insisted on using GXT (due to its nice colors and theme) on a project that will most likely become very big with lots of screens. I am against the idea of a javascript only client, especially when the javascript is generated from Java code. I have tried to advice him that we use something like wicket whereby we construct the screens with html but put in ajax where and when neccessary.
How viable is such a JavaScript client? I understand that JavaScript was intended for minor web page enhancements, and not all browsers, especially mobile devices have complete support for JavaScript.
Yes, it is viable for certain applications. Consider Gmail, Google Docs and Google Maps as typical applications where this works, and is probably the most feasible approach.
Some rich UI JavaScript frameworks, such as Ext JS also rely on this technique.
I've built javascript only web apps for ages.
First in SAP projects for big multinationals. And now on a new project:https://beebole-apps.com?demo
So yes it is powerful and viable.
Javascript-only webapp can be extremely powerful, and it's viable for certain applications, say, an Instant-Messenger webapp?
You mentioned that there are lots of screens in your web-app. One of the advantages from GWT/GXT is the fact that you can unit test your UI-layer with JUnit. This is an extra testing you can do on top of, say, Selenium. This is essential if you'd like to make UI testing a part of the continuous integration process, and, as the team grows, you'll definitely want to have tests around to make sure everything works (At least in theory.)
However, if what your boss meant to do is to build an in-house, custom Javascript engine using GWT's JavaScript Native Interface (Link), then I'm not sure...
Another advantage with GWT-like-engine over Wicket is that you can rely on HTML-code-gen to generate standard-compliant (In theory) HTML code. With framework like Wicket, it is hard to ensure every single developer on the team to author good HTML code - Especially when the team gets bigger.
Disclaimer: I'm a member of the Vaadin team.
Our Timeline demo is a good example of what can be achieved with Vaadin and GWT in client side, but I think all of the options presented in this discussions are viable given enough time.
Since you are going to start a big project you should build a simple proof-of-concept app with each of the relevant frameworks. If your PoC includes at least some of the more complex use cases you'll probably can make a pretty informed choice based on the experiences you get while building them.
I urge you to at least evaluate Vaadin. With it you write only server-side Java code and Vaadin will create a slick and professional browser UI for you. Client side can be easily extended using standard GWT (also pure Java), and there are no HTML templates, tag libraries or XML configuration involved at all. A Vaadin UI is fully Ajax'ed and lazy loading out of the box, and it easily integrates with any server side technologies, eg. Spring.
In addition to the development model advantages you get top-notch documentation, a bi-weekly update schedule, a very lively community filled with helpful experts, 100+ useful open source add-ons, and a 10 year old backing company with help on hand should you need it.
We have a few dozen web apps on multiple servers/platforms owned by 5 teams at our company and want to merge them into a single site. The UI part is straightforward - a common header with login/status info, tabs for the major sections of the site, and yui menus for navigation within a section.
The hard part is finding a way to do this while making minimal changes to the existing apps, which are easily breakable and a pain to deploy. We want to minimize updates to the apps and try to get it right the first time.
The only working solution we have now is to include a Javascript file to write the site header/navigation at the top of the page, which lets us easily deploy changes to all of the apps:
script src="..../site/include?appid=xxx" // app id determines which tab/navigation to display
Is there a better way to do this, especially one with better performance than remote dynamic Javascript that writes the entire page header? Are there existing frameworks to simplify this?
Consider using a portal framework like uPortal. You could aggregate all those webapps -- no matter what technologies they're written in -- by leveraging a web proxy solution.
This suggestion might be overkill if your needs are really & truly simple; but uPortal (and others) provide scores of additional functions -- like administration, statistics, SSO, and integrations with other platforms and services -- that quickly add to their attractiveness.