# Unobtrusive javascript/Ajax in Rails

**URL:** <https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308>\
**Category:** Rails\
**Created:** [July 6, 2008, 4:07pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308 "2008-07-06T16:07:57Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 6, 2008, 4:07pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/1 "2008-07-06T16:07:57Z")

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Hello list,

I have been reading a lot about web standards lately, and specially  
about  
unobtrusive javascript.

It essentially tells you to get rid of javascript in the view layer  
((X)HTML), including event assignment.

Considering all of the default prototype Rails helpers don’t cope with  
these  
rules, what would be the best way to implement unobstrusive javascript  
in a  
Rails application ? Overriding these helper methods ?

I have found the ujs4rails plugin, but it doesn’t seem to be usable as  
of  
now, with Rails 2.x. The last update was back on 2006. Too bad as it  
seems  
to be a really cool project.

Any hints greatly appreciated!

Thanks,

Marcelo.

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 6, 2008, 4:16pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/2 "2008-07-06T16:16:44Z")

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Marcelo de Moraes S. wrote:

> It essentially tells you to get rid of javascript in the view layer  
> ((X)HTML), including event assignment.

That is UJS’s marketing pitch. While there’s a lot of benefit in letting  
a Ruby  
generator build your Javascript for you, there’s still no benefit in  
hiding  
absolutely all of it. If your View needs a custom onload=‘foo()’, just  
go ahead  
and write a little JS.

> Any hints greatly appreciated!

Also, make sure your unit tests cover your JS.

(Unit tests - not “acceptance tests”. They should not raise a browser  
just to  
spot-check things…)

–  
Phlip  
[http://assertxpath.rubyforge.org/](http://assertxpath.rubyforge.org/)

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 6, 2008, 9:24pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/3 "2008-07-06T21:24:45Z")

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On Jul 6, 2008, at 7:07 AM, Marcelo de Moraes S. wrote:

> unobstrusive javascript in a Rails application ? Overriding these  
> helper methods ?
> 
> I have found the ujs4rails plugin, but it doesn’t seem to be usable  
> as of now, with Rails 2.x. The last update was back on 2006. Too bad  
> as it seems to be a really cool project.
> 
> Any hints greatly appreciated!

I normally hook the loaded event in my javascript. So, for example  
(Prototype):

document.observe(‘dom:loaded’, function() {  
// set up event watchers, etc.  
}

or for jQuery:

jQuery.document(ready){function() {  
// set up event watchers, etc.  
}

This does not address Philip’s concerns with respect to having  
JavaScript wrapped into unit tests, but it is a viable way to hook  
things up in an unobtrusive way.

Hope this helps.

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 6, 2008, 9:33pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/4 "2008-07-06T21:33:33Z")

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s.ross wrote:

> document.observe(‘dom:loaded’, function() {  
> // set up event watchers, etc.  
> }

Yet note that’s still raw JS - not hidden inside a Ruby layer.

> This does not address Philip’s concerns with respect to having  
> JavaScript wrapped into unit tests, but it is a viable way to hook  
> things up in an unobtrusive way.

It would work fine. Suppose you need this:

document.observe(‘dom:loaded’, function() {  
think\_about\_record(\<%= my\_record.id %\>);  
}

Now you could test with:

assert\_match @response.body, /think\_about\_record…42/

That would spot-check the business logic went into the view at the right  
spot.  
That’s quite enough coverage to defend this feature from refactors and  
upgrades.

–  
Phlip

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 6, 2008, 11:19pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/5 "2008-07-06T23:19:13Z")

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I highly reccomend LowPro. LowPro is unobtrusive javascript at its best.

[http://www.danwebb.net/2006/9/3/low-pro-unobtrusive-scripting-for-prototype](http://www.danwebb.net/2006/9/3/low-pro-unobtrusive-scripting-for-prototype)

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 7, 2008, 12:14am UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/6 "2008-07-07T00:14:46Z")

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The problem is that these UJS efforts for Rails all seem to have stopped  
in  
time (2006, to be specific). People have lost interest? Why?

The one thing that bugs me is the effort I would need to implement ujs  
in  
Rails currently.

Well, let’s see how it goes… I may also not worry about ujs too much  
right  
now too.

Thanks!

Marcelo.

On Sun, Jul 6, 2008 at 6:19 PM, Nathan E. \<

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**Author:** ![mhfs](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/m/b2d939/32.png) [@mhfs](https://www.ruby-forum.com/u/mhfs)\
**Post date:** [July 6, 2008, 10:14pm UTC](https://www.ruby-forum.com/t/unobtrusive-javascript-ajax-in-rails/142308/7 "2008-07-06T22:14:05Z")

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Thank you guys for the helpful insights! I appreciate your help.

Marcelo.