/*** 獲取相鄰元素* @param ele 參考物元素* @param type 類型，上一個(1)or下一個(0)* @return 返回查找到的元素Dom對象，無則返回null*/function getNearEle(ele, type) {  type = type == 1 ? "previousSibling" : "nextSibling";  var nearEle = ele[type];  while(nearEle) {    if(nearEle.nodeType === 1) {      return nearEle;    }    nearEle = nearEle[type];    if(!nearEle) {      break;    }  }  return null;}/*** 獲取當前執行對象的上一個元素*/function prev() {  return getNearEle(this, 1);}/*** 獲取當前執行對象的下一個元素*/function next() {  return getNearEle(this, 0);}// var ele = document.getElementById("xxx");// var prevElement = prev.call(ele);// var nextElement = next.call(ele);