let jsonArr = [
  {
     "classid": "87",
     "classname": "办事处/华北区/北京办事处/北京客服部"
  },
  {
     "classid": "86",
     "classname": "办事处/华北区/北京办事处/北京销售部"
  }
              ]
let arr = [];
for (var i in jsonArr) {
	arr.push(jsonArr[i].classname)
 }