code: function getOuterWidth(el, defaultValue) {
      var width = this.getWidth(el, defaultValue);
      var bLeft = parseFloat(this.getStyle(el, 'borderLeftWidth')) || 0;
      var pLeft = parseFloat(this.getStyle(el, 'paddingLeft')) || 0;
      var pRight = parseFloat(this.getStyle(el, 'paddingRight')) || 0;
      var bRight = parseFloat(this.getStyle(el, 'borderRightWidth')) || 0;
      return width + bLeft + bRight + pLeft + pRight;
    }
docs: 获取外层宽度
  @param  {HTMLElement} el dom节点
  @param  {Number} defaultValue 默认值
  @return {Number} 宽度