jQuery事件click后面跟上了一串

/* FILEUPLOAD DATA-API
  * ================== */

  $(function () {
    $('body').on('click.fileupload.data-api', '[data-provides="fileupload"]', function (e) {
      var $this = $(this)
      if ($this.data('fileupload')) return
      $this.fileupload($this.data())

      var $target = $(e.target).is('[data-dismiss=fileupload],[data-trigger=fileupload]') ?
        $(e.target) : $(e.target).parents('[data-dismiss=fileupload],[data-trigger=fileupload]').first()
      if ($target.length > 0) {
          $target.trigger('click.fileupload')
          e.preventDefault()
      }
    })
  })

'click.fileupload.data-api'这是什么用法？