SOURCE

function Node(element){
    this.element = element;
    this.next = null;
    this.previous = null;
}
function LList(){
    this.head = new Node('head');
    this.find = find;
    this.insert = insert;
    this.remove = remove;
    this.display = display;
    this.findLast = findLast;
    this.dispReverse = dispReverse;
}
function find(item){
    var currNode = this.head;
    while(currNode.element != item){
        currNode = currNode.next;
    }
    return currNode;
}

function insert(newElement,item){
    var newNode = new Node(newElement);
    var current = this.find(item);
    newNode.next = current.next;
    newNode.previous = current;
    current.next = newNode;
}

function display(){
    var currNode = this.head;
     while(!(currNode.next == null)){
         console.log(currNode.next.element);
        currNode = currNode.next;
    }
}

function remove(item){
    var currNode = this.find(item);
    if(!(currNode.next == null)){
        currNode.previous.next = currNode.next;
        currNode.next.previous = currNode.previous;
        currNode.next = null;
        currNode.previous = null;
    }
}
function findLast(){
    var currNode = this.head;
    while(!(currNode.next == null)){
          currNode = currNode.next;
    }
    return currNode;
}

function dispReverse(){
    var currNode = this.head;
    currNode = this.findLast()
     while(!(currNode.previous == null)){
         console.log(currNode.element);
        currNode = currNode.previous;
    }
}

var aaa = new LList();
aaa.insert('aaa','head');
aaa.insert('bbb','aaa');
aaa.insert('ccc','bbb');
aaa.insert('ddd','ccc');
aaa.display();
console.log('---------');
aaa.remove('ccc');
aaa.display();
console.log('---------');
 
aaa.dispReverse();