function Node(element) {        this.element = element;// element 用来保存节点上的数据        this.next = null;//用来保存指向下一个节点的链接    }    function LList() {        this.head = new Node("head");        this.find = find;        this.insert = insert;        //this.remove = remove;remove()若是未定义会出错！！必须注释掉        this.findPrevious = findPrevious;        this.remove = remove;        this.display = display;    }    function find(item) {        var currNode = this.head;        while (currNode.element != item) {            currNode = currNode.next;        }        return currNode;    }    function insert(newElement, item) {
   //在item节点后插入newElement新节点        var newNode = new Node(newElement);//插入元素必先创建节点        var current = this.find(item);        //添加元素不需要考虑item不存在的情况，因为当item不存在时，可在链表末尾添加        newNode.next = current.next;//用链表的思想去考虑，不要从赋值的角度考虑        //node.next()可看作指向下一个节点的链接&&下一个节点        //理解为链接指向新节点，newNode.next链接指向current.next节点        current.next = newNode;//此处断开原链接    }    function display() {        var currNode = this.head;        while (!(currNode.next == null)) {            document.write(currNode.next.element + "
");            currNode = currNode.next;        }    }    var cities = new LList();    cities.insert("Conway", "head");    cities.insert("Russellville", "Conway");    cities.insert("Alma", "Russellville");    cities.display();    document.write("*********" + "
");    function findPrevious(item) {        //删除元素需要找到该元素前面的节点        var currNode = this.head;        while ((currNode.next.element != item)) {            currNode = currNode.next;        }        return currNode;    }    function remove(item) {        var prevNode = this.findPrevious(item);        if (prevNode.next != null) {            prevNode.next = prevNode.next.next;        }    }    cities.insert("lelei", "Alma");    cities.remove("Alma");    cities.display();    /* 上述程序运行结果如下：    Conway    Russellville    Alma     *********    Conway    Russellville    lelei*/

关于添加节点的图示理解：