A simple polyfill for enabling the «img srcset 2x» attribute in browsers which does not yet support it

SrcsetSimplePolyfill

SrcSetSimplePolyfill =
  init : () ->
    img = new Image()
    if 'srcset' of img is no and (window.devicePixelRatio || 1) > 1
      images = document.querySelectorAll('img');

      for image in images
        @swapImagSrc image

  swapImagSrc : (image) ->
    comp = @parseURL image
    if comp
      image.src = comp

  parseURL : (url) ->
    set = url.getAttribute 'srcset'
    exp = new RegExp /https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{2,256}\.[a-z]{2,6}\b([-a-zA-Z0-9@:%_\+.~,#?&//=]*)?/gi
    set.match(exp)[0];