Retina Coffeescript hingey

<span class="image" style="background-image: url(<!-- @path hammer-1-5.jpg -->)" data-style="background-image: url(<!-- @path hammer-1-5.jpg -->)" data-retina-style="background-image: url(<!-- @path hammer-1-5@2x.jpg -->)"><a href="<!-- @path hammer-1-5.html -->"></a></span>

retinafy = ->
if window.previousDevicePixelRatio != window.devicePixelRatio
window.previousDevicePixelRatio = window.devicePixelRatio
$('[data-src][data-retina-src]').each () ->
$(this).attr 'src', $(this).data(if window.devicePixelRatio > 1 then 'retina-src' else 'src')
$('[data-style][data-retina-style]').each () ->
$(this).attr 'style', $(this).data(if window.devicePixelRatio > 1 then 'retina-style' else 'style')
setInterval retinafy, 1000
retinafy()