Archive for the ‘javascript’ Category

Onchange Event Fired from Select Field in Rails Form

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Posted 04 Mar 2010 — by admin
Category Ruby on Rails, javascript

In the view there is a regular Rails form and a javascript function that will be triggered when the country select field is changed. The javascript function will make an ajax request to the country_select url with the country code passed as the id variable, e.g., /country_code/us for the United States. I’m also using the Carmen plugin for this example which will provide a list of countries and their respective states/provinces. Not all countries are full supported. More information on Carmen can be found at http://autonomousmachine.com/2009/4/1/carmen-a-rails-plugin-for-geographic-names-and-abbreviations and http://github.com/jim/carmen

<%form_for(@model) do |f| %>
<script type="text/javascript" charset="utf-8">
  function change_state_select(state_code
  {
    new Ajax.Request('/country_select/'+state_code
    {
      method: 'get',
      onSuccess: function(transport) {
        $('state_select').replace(transport.responseText);
      }
    });
  }
 </script>
 <%= f.select :country,
   Carmen::COUNTRIES,
   {},
   { : onchange => "change_state_select(this.options[this.selectedIndex].value);" }
%>
<div id='state_select'></div>

***Note the : onchange should really be one word but an emoticon shows up otherwise :o nchange :( ***
Since not all countries are supported I need to execute some conditional logic in the action country_select. If the country is supported I’ll return a snippet of html containing a select field that my form will use. If the country is not supported I’ll return a text field so that the user can write in their state/province. 

class CountrySelectController < ApplicationController
  def country_selecet
      begin
         @states = Carmen::states(params[:id])
      rescue
         @states = nil
      end
      render :partial => "country_select/states"
  end
end

In the final partial that is rendered there is either a select field or a text field

<div id="state_select">
  <% if @states.nil? %>
    <%= text_field_tag :model, :state %>
  <% else %>
    <%= select :model, :state, Carmen::states(@states)%>
  <% end %>
</div>
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Accessing Links in Nested TD Cells with Prototype

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Posted 17 Nov 2009 — by admin
Category javascript

There must be a better way to do the following with PrototypeJS. I want to loop over nested links inside of table td cells and apply a class to the row that the link is in when the link is clicked. If a user clicks on another link the class will be removed and applied to the current table row.

The code below works but I think it seems hackish. Any thoughts on improving this code?

Here is the link to the pastie http://pastie.org/703316 

# This is the table with haml markup
%table
  %tr
    %td
       info
    %td
      = link_to "be clicked", remote_request_goes_here_path

And the Js

	$$("td.filter_link > a").each(function(element){
		Event.observe(element, "click", function(event){
			$$("td.filter_link").each(function(el){
				if(el != this){
					el.up().removeClassName("turnwhite");
				}
			});
                       // apply the turnwhite class to the table row
			this.up().up().addClassName("turnwhite");
		});
	});
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