Select

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle',
  selectedColor: 'green',
  colors: ['red','green','blue'],
  actions: {
    selectColor(evt) {
      this.set('selectedColor', evt.target.value);
    }
  }
});

application.template.hbs

<h1>Welcome to {{appName}}</h1>
<br>
<br>
{{outlet}}
<br>
<br>

<select onchange={{action "selectColor"}}>
{{~#each colors as |color|~}}
<option selected={{is-selected color selectedColor}} value={{color}}>{{color}}</option>
{{~/each~}}
</select>

helpers.is-selected.js

import Ember from 'ember';
const { Helper } = Ember;

export default Helper.helper(([a, b]) => {
  return a == b ? 'selected' : null;
});

twiddle.json

{
  "version": "0.4.11",
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/1.13.11/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/1.13.9/ember-template-compiler.js"
  }
}