Test srcset in Firefox!

Getting Started

1. Download a nightly build of Firefox (33a1) from nightly.mozilla.org
2. Open the developer toolbar (shift + F2) or Tools > Web Developer > Developer Toolbar in your menu.
3. In the developer toolbar, enter pref set dom.image.srcset.enabled true

srcset and sizes in action!

srcset

src="foo.jpg" srcset="bar.jpg 2x"

srcset="foo.jpg 1x, bar.jpg 2x"