constructor (el, options) {
    this.options = options
    this.$el = $(el)
    this.$el_ = this.$el.clone()
    this.timeoutId_ = 0
    this.timeoutFooter_ = 0
  }
@author zhixin wen <wenzhixin2010@gmail.com>
version: 1.24.1
https://github.com/wenzhixin/bootstrap-table/