testing fixed headers

application.controller.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName:'Ember Twiddle'
});

application.template.hbs

{{my-component}}

my-component.component.js

import Ember from 'ember';

export default Ember.Component.extend({
  didInsertElement() {
    console.log('inserted element');
    
    Ember.$('.container').on('scroll', function() {
      const scrollTop = Ember.$('.container').scrollTop();
      Ember.$('.header').css('top', scrollTop);
    });
    
    return this._super(...arguments);
  },
  
  willDestroyElement() {
    return this._super(...arguments);
  }
});

my-component.template.hbs

<div class="container">
  <div class="header">
    <div class="cell" style="left: 0;">header</div>
    <div class="cell" style="left: 300px;">header</div>
    <div class="cell" style="left: 600px;">header</div>
    <div class="cell" style="left: 900px;">header</div>
    <div class="cell" style="left: 1200px;">header</div>
  </div>
  <div class="content">this is the content</div>
</div>

styles.app.css

* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; margin: 0; }
.ember-view { width: 100%; height: 100%; }

.container {
  width: 100%;
  height: 100%;
  overflow: scroll;
}

.header       { position: relative; }
.header .cell { position: absolute; }

.header  { height: 50px;   }
.content { height: 5000px; background-color: #bbb; }

.header .cell {
	width: 300px;
  height: 50px;
	border-right: solid 1px black;
	background-color: tomato;
}

twiddle.json

{
  "version": "0.5.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.11.3/jquery.js",
    "ember": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember.debug.js",
    "ember-data": "https://cdnjs.cloudflare.com/ajax/libs/ember-data.js/2.2.0/ember-data.js",
    "ember-template-compiler": "https://cdnjs.cloudflare.com/ajax/libs/ember.js/2.2.0/ember-template-compiler.js"
  }
}