How do I get the selected value from a collection_select in the view for an Ajax.Updater call?

rubyonrails-talk
1

I have the classic issue where I have two select boxes, the second's contents dependent on the first. I found some same code that works fairly well using an Ajax.Updater. However, I need to pass in the selected value of the original select list to the ajax call. I am trying to use this[this.selectedIndex].value but keep getting a "undefined local variable or method `this' for #<#<Class:0x3143860>: 0x3143838>".

Any ideas? Here's a my snippet of code from my view.

          collection_select('product',                             'departments',                             @departments,                             :id, :name,                             {:prompt => "Select"},                             html_options =                                {                                    :onChange => "new Ajax.Updater('categories_span',                                                 '/mgs/ department_changed/'" + this[this.selectedIndex].value + ",                                                 {asynchronous:true, evalScripts:true});"                                })         %>

Thanks,

Scott

2

Hello Scott,

Any ideas? Here's a my snippet of code from my view.

You're falling into the classic hole of Ruby vs JavaScript code.

          collection_select('product',                             'departments',                             @departments,                             :id, :name,                             {:prompt => "Select"},                             html_options =                                {                                    :onChange => "new Ajax.Updater('categories_span',                                                 '/mgs/ department_changed/'" + this[this.selectedIndex].value + ",                                                 {asynchronous:true, evalScripts:true});"                                })         %>

Your onChange parameter must be a string that will be evaluated client-side. The way your wrote it, you are calling this on the Rails View object, which is the error you are getting.

You must either: escape your quotes, or use the %Q() operator to enable you to use quotes inside a string, without escaping:

:onChange => %Q( new Ajax.Updater('categories_span', '/mgs/department_changed/' + this[this.selectedIndex].value, {asynchronous:true, evalScripts:true)

Hope that helps !

3

Hi François,

Thanks for getting back to me so quickly.

That sort of worked. When I wrap in the %Q, I get the following in the source of the rendered page:

      <select id="product_departments" name="product[departments]" onChange="new Ajax.Updater('categories_span',                                                 '/mgs/ department_changed/' + this[this.selectedIndex].value + ,                                                 {asynchronous:true, evalScripts:true});">

Unfortunately, the controller is called when the item's selection is changed.

If I subsitute the this[this.selectedIndex].value with 4 for example, just to see if it works, it does in fact update the second select box.

Any other ideas?

Thanks again,

Scott