Do EmberJS really need jQuery? Is it possible to leave it out?
Ember.js requires jQuery for two reasons:
- We rely on it heavily in the Ember/Handlebars integration for inserting and modifying DOM elements. I personally am not interested in dealing with cross-browser DOM manipulation bugs, but the jQuery team excels at it.
- By having a standard DOM manipulation library in jQuery, developers can move between different Ember.js apps and rely on the fact that they have a battle-tested, cross-platform library underneath them.
If you are concerned about size, I’d recommend investigating the new jQuery 2.0, which has the ability to do custom builds without features such as animation.
Sure, this is a common sense 
Another question - when html templates (a part of web components) become available, will Ember continue to use Handlebars?