Comments on: Data from Javascript to Rails?

Question: Data from Javascript to Rails?

jxpx777 — Fri, 23 Feb 2007 18:49:56 -0800

How can I pass data created via javascript to my Rails application?

I am working on a Rails application that relies on user input for some data that needs to store in the database. The data is created by the user clicking inside a div at various points, and the data that I need to store is the mouse coordinates where the user clicks.

So, the view loads and the user clicks various places. Of course, capturing the mouse position is easily accomplished. Where I am stuck is in how to pass the array of data that I created wtih Javascript to my Rails controller for processing.

Any help is greatly appreciated.

By: IshmaelGraves

IshmaelGraves — Fri, 23 Feb 2007 19:01:41 -0800

JSON is great for this sort of thing. Pass it in via AJAX or as a GET or POST parameter with a form submission.

By: cschneid

cschneid — Fri, 23 Feb 2007 20:48:24 -0800

If you want to submit the whole page, throw the data into a hidden form element, and make the submit just send in the form. Then it's like any other. If you need to do it asyncronously, just use ajax. Just use the normal ajax commands in rails (remote_function looks about right) to call the controller w/ the args.

By: beerbajay

beerbajay — Fri, 23 Feb 2007 22:12:57 -0800

Seconding what cshneid said. You use the javascript to fill in the "value" attribute of hidden form fields (using normal DOM functions), then submit the form at the appropriate time. Same as any other form processing.

By: gaby

gaby — Sat, 24 Feb 2007 05:17:08 -0800

Ref JSON, you may need to use POST to pass it as there's a limit on the size of a URL, and a JSON object could become quite large. As cschneld suggested, stick it in a hidden form element and POST it into Rails.

I'd suggest using the ScriptAculous libraries to do this:

<input type="hidden" id="json" name="json" value="">

<script>

// Whatever your data object is here
var my_data = { test: ["one","two"] };

// Assuming JSON is a class that can encode or decode
// json data.
$( "json" ).value = JSON.encode( my_data );

</script>