Select fields, Coffeescript and Cocoon

Hello, I have select field which after a choice happened, feeds another select field.

Using the gem Cocoon to duplicate this set of select fields. My problem now is to find a solution that the coffee script supplies values for each select field-set separately.

My code:

form <%= render ‘usergroup_fields’, :f => usergroup %> <%= link_to_add_association “Add Group”, f, :usergroups %>

usergroup_fields: <%= f.select :ops_group_id, options_for_select(@groups……{ id: ‘ops_select’ } %> <%= f.select :oncall_id, options_for_select(@oncalls….{ id: ‘oncalls_select’ } %>

Coffee: $ → $(document).on ‘change’, (‘#ops_select’), → $.ajax ‘/projects/update_oncalls/’, type: ‘GET’ dataType: ‘script’ data: { ops_group_id: $(“#ops_select option:selected”).val()

update_oncalls.js $(“#oncalls_select”).empty().append(“<%= escape_javascript(render(:partial => @oncalls)) %>”)

I think I need some reference to supply to the script but don’t know how. Any help would be great. Thanks

Hello, I have select field which after a choice happened, feeds another select field.

Using the gem Cocoon to duplicate this set of select fields. My problem now is to find a solution that the coffee script supplies values for each select field-set separately.

My code:

form <%= render 'usergroup_fields', :f => usergroup %> <%= link_to_add_association "Add Group", f, :usergroups %>

usergroup_fields: <%= f.select :ops_group_id, options_for_select(@groups…..{ id: 'ops_select' } %> <%= f.select :oncall_id, options_for_select(@oncalls….{ id: 'oncalls_select' } %>

Coffee: $ ->   $(document).on 'change', ('#ops_select'), ->     $.ajax '/projects/update_oncalls/',       type: 'GET'       dataType: 'script'       data: {         ops_group_id: $("#ops_select option:selected").val()

update_oncalls.js $("#oncalls_select").empty().append("<%= escape_javascript(render(:partial => @oncalls)) %>")

I think I need some reference to supply to the script but don’t know how. Any help would be great. Thanks

One thing to remember, conceptually, is that you cannot replace the "innards" of a select as if they were HTML without destroying its ability to react correctly to scripting or user input. The only "bulletproof" way to update the contents of a select is to set its options collection length to 0, then iterate over your collection of data, using the new Option(text,value) constructor to build each option. Doing it any other way will end in tears. This has nothing to do with CoffeeScript or JavaScript and everything to do with browsers and the DOM.

Walter

Thanks Walter..

may be you have some code to demonstrate..so I get the idea ?

One thing to remember, conceptually, is that you cannot replace the "innards" of a select as if they were HTML without destroying its ability to react correctly to scripting or user input. The only "bulletproof" way to update the contents of a select is to set its options collection length to 0, then iterate over your collection of data, using the new Option(text,value) constructor to build each option. Doing it any other way will end in tears. This has nothing to do with CoffeeScript or JavaScript and everything to do with browsers and the DOM.

Walter

Thanks Walter..

may be you have some code to demonstrate..so I get the idea ?

Sure. This is using Prototype.js for clarity, you'll have to guess (I don't know) how to describe it in jQuery, if that's your thing.

  <select name="foo" id="foo" size="1">     <option value="1">One</option>     <option value="2">Two</option>     <option value="3">Three</option>     <option value="4">Four</option>   </select>

  var new_options = [{"value": "5", "text": "Five"}, {"value": "6", "text": "Six"}];   var foo = $('foo');   foo.options.length = 0;   new_options.each(function(opt){     foo.options[foo.options.length] = new Option(opt['text'], opt['value']);   });

Walter