   constructor: (@elementSelector) ->
     @value = 0
     @opacity = 1
+    @content = ''
     @speed = 300
     @install()
 

    setTimeout =>
      @value = 0
      @opacity = 1
      @_withSpeed(0, @_updateStyle)
    , @speed

  _startTrickle: ->

    @speed = originalSpeed
    result

  _updateStyle: (forceRepaint = false) ->
    @_changeContentToForceRepaint() if forceRepaint
    @styleElement.textContent = @_createCSSRule()

  _changeContentToForceRepaint: ->
    @content = if @content is '' then ' ' else ''

  _createCSSRule: ->
    """
    #{@elementSelector}.#{className}:before {
      content: '#{@content}';
      position: fixed;
      top: 0;
      left: 0;
