CODEWITHSUNDEEP
asp.net-mvcajaxprogressive-enhancement
Major Productions
Major Productions

Reputation: 6042

Progressive enhancement - what to do when JavaScript is off?

I understand what progressive enhancement is, I'm just fuzzy on some of the details in actually pulling it off. Of course, that could be because I'm looking at it in the wrong way. Let me try to explain my difficulty with a hypothetical:

ASP.NET MVC site. I have a view that has tabbed navigation. Each tab is for a movie category/genre which displays 5-10 links to movies in that category. The movie data is obtained through Netflix's Odata.

My initial thought is to use Ajax to pull and parse the JSON from the proper OData GET requests when each tab is clicked. How would I provide a non-JavaScript version of that? Is it even possible?

For simpler requests where JSON isn't necessary - like, say, having a user log into the system - I see how I could simply set a cookie and dynamically change the page based on it to reflect the change. But what if I need to return and parse JSON? How do I provide an alternative?

Upvotes: 0

Views: 468

Answers (2)

Jon
Jon

Reputation: 437386

The deal with progressive enhancement is that your server side must be fully capable of generating every last bit of HTML that appears in all of your pages. This is obvious, since otherwise (if JS is turned off) there will be no part of your application capable of doing said rendering.

Since the server side must know how to render everything, it doesn't make much sense to generate things (DOM elements/HTML) on the client side from JSON responses the server gives you. Why repeat yourself?

This brings us to the logical conclusion that when doing dynamic updates on the client, you need to get ready-made HTML from the server (since the rendering logic is over there) and insert it into the DOM as appropriate. You are then free to work on the newly inserted elements with jQuery and enhance them all you want.

So -- forget about parsing JSON on the client, otherwise you 're locking yourself out of progressive enhancement. If you want to call a third party, have the server be your intermediary: call the server with all the necessary information for it to call the third party and get ready-made HTML back.

If you do this, then the server can of course provide non-JS versions of everything on your site with no problem. Total non-reliance on JS achieved.

Upvotes: 5

Chad Ruppert
Chad Ruppert

Reputation: 3680

There is no JSON without JS, by definition (JavaScript Object Notation). Without JS you won't make AJAX calls. Your pages will render as is, just like oldschool sites.

If you need to do this progressively, you will have to call the odata service server-side, and provide .net objects to the site in viewdata, or your viewmodel, and have your views/partials render it.

In ASP.Net MVC actions, the httpcontext available via the controller will have a property on this path: this.HttpContext.Request.IsAjaxRequest() and can be used to test whether you want to return a view or just json data, or whatever type of ActionResult you want. This can be an excellent timesaver for building progressive enhancement style sites.

Upvotes: 1

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