     if childrenLength == 1 and @options.allowBlank
       @$('.extra-buttons .btn-primary').prop('disabled', false);
       conditionAvailabel = true
-    if @options.allowBlank and @$el.find(@subviewContainer).children().length != 0
+    if @options['allowBlank'] and @$el.find(@subviewContainer).children().length != 0
       @$('.extra-buttons .btn-danger').prop('disabled', false)
       conditionAvailabel = true
-    if @options.limit and childrenLength == @options.limit
+    if @options['maxNumber'] and childrenLength == @options.maxNumber
       @$('.extra-buttons .btn-primary').prop('disabled', true)
+      conditionAvailabel = true
+    if childrenLength == @options['minNumber']
+      @$('.extra-buttons .btn-danger').prop('disabled', true)
       conditionAvailabel = true
     if conditionAvailabel
       return

      options['subviewOptions'] = {}
    if not options['allowBlank']?
      options['allowBlank'] = false
    if options['limit']?
      options['limit'] = parseInt options['limit']
    @options = options

  render: =>
    @$el.html(@template())
    
    # Initial the first subview
    if not @options['allowBlank']
      @add()
    @redrawExtraButtons()
    @
  

    if evt.target
      $el = $(evt.target)
    else
      # Assume the latest delete button
      $el = @$('.extra-buttons:last .btn-danger')
    @undelegateEvents()
    if @options.allowBlank and @$el.children().length == 1
      el = $el.parents('.control-group').find(@subviewContainer).children()
