対象の要素をスピナー画像に置き換える的な

spinner.js.coffee

class Spinner
  constructor: (element) ->
    @element = element
    @spinner = $('<div class="spinner"><img src="/assets/spinner.gif"></div>')

  show: ->
    @spinner.css
      width: @element.width(),
      height: @element.height()
    @spinner.fadeIn()
    @element.replaceWith(@spinner)
    @element.fadeOut()

  hide: ->
    @element.fadeIn()
    @spinner.replaceWith(@element)
    @spinner.fadeOut()