How to pass a variable from controller to javascript within a view?

Question

I have an array @fields which has text and an id, asset_id. To pass local variables from controller to view in render we use

render(:template => "assets/invalid", :locals => {:asset_id => params[:id], :fields => @fields})

The view is

<div id="panel">
  <script>
    alert('Invalid values for ')
    window.location = "../assets/" 
  </script>
</div>

This should generate a popup box. However, I want the popup box to redirect to "../assets/asset_id" and also display 'Invalid values for + fields'

The following doesn't work,

<div id="panel">
  <script>
    var fields = fields
    var asset_id = asset_id 
    alert('Invalid values for ' + fields )
    window.location = "../assets/" + asset_id 
  </script>
</div>

Yes, I do see it. The alertbox redirects to ../assets/. I want it to redirect to ../assets/asset_id. — absessive
– absessive, Commented Oct 15, 2012 at 16:53
Post how you are getting the asset_id and how you want to send it. Since its html.erb you can just grab it. — Sully
– Sully, Commented Oct 15, 2012 at 16:56
The assets_id is from the controller. I want to send it to the script in the view to create the location of that asset, i.e. redirect to that ID page. The :local within render should send it to the view, shouldn't it? The JS has to create that link for window.location to redirect to. — absessive
– absessive, Commented Oct 15, 2012 at 17:02

Victor Moroz · Accepted Answer · 2012-10-15 17:13:29Z

3

Could it be as simple as this?

<div id="panel">
  <script>
    var fields = <%= fields.to_json %>
    var asset_id = <%= asset_id.to_json %>
    alert('Invalid values for ' + fields )
    window.location = "../assets/" + asset_id 
  </script>
</div>

UPDATE And by the way, why do you need to pass fields or params as a local variable, why not to use @fields in your view?

edited Oct 15, 2012 at 17:13

answered Oct 15, 2012 at 17:04

Victor Moroz

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3 Comments

absessive Over a year ago

The .to_json method isn't working. The view (alert box) doesn't show up. If I kept it as just fields as @Viren said, the alert box says 'Invalid values for undefined'.

Victor Moroz Over a year ago

Check page source -- what it's being converted to

absessive Over a year ago

fields is an array of strings and asset_id is a string

Derrick W · Accepted Answer · 2012-10-15 17:29:48Z

1

An approach I have used in a couple apps where it's necessary for the client code to use server data is to build a hash and render it into a json literal on the page and have all my JS reference that object. It's the same approach as mentioned above but it's a bit cleaner because you don't have to mix a lot of server tags into your JS code. Easier to read and maintain.

answered Oct 15, 2012 at 17:29

Derrick W

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Comments

Viren · Accepted Answer · 2012-10-15 17:04:57Z

0

What wrong with this

<div id="panel">
  <script>
    var fields = fields
    var asset_id = <%= asset_id %> 
    alert('Invalid values for ' + fields )
    window.location = "../assets/" + asset_id 
  </script>
</div>

Now you can pass data to html for advance thing you can use something like gon check out gon gem it might help

answered Oct 15, 2012 at 17:04

Viren

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2 Comments

Phrogz Over a year ago

The to_s of an array is not consistently parseable as JS across Ruby versions. Though the inspect output of an array mostly is, it's safer to go with to_json.

Viren Over a year ago

@Phrogz Point very well Expected

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