var DoublyLinkedList = function(prev, next, data, head){

this.prev = null;

this.next = null;

this.data = null;

this.head = false;

this.tail = false;

this.setPrev = function(prev){

this.prev = prev;

}

this.setNext = function(next){

this.next = next;

}

this.setHead = function(head){

this.head = head;

}

this.setTail = function(tail){

this.tail = tail;

}

/*var getPrev = function(){

return this.prev;

}

var getNext = function(){

return this.next;

}*/

this.setData = function(data){

this.data = data;

}

}

var nodeOne = new DoublyLinkedList();

nodeOne.setData(5);

nodeOne.setHead(true);

var nodeTwo = new DoublyLinkedList();

nodeTwo.setData(51);

nodeOne.setNext(nodeTwo);

nodeTwo.setPrev(nodeOne);

var nodeThree = new DoublyLinkedList();

nodeThree.setData(33);

nodeTwo.setNext(nodeThree);

nodeThree.setPrev(nodeTwo);

var nodeFour = new DoublyLinkedList();

nodeThree.setNext(nodeFour);

nodeFour.setData(91);

nodeFour.setNext(null);

nodeFour.setPrev(nodeThree);

nodeFour.setTail(true);

document.querySelector('#nodeOne').innerHTML = "Getting value through Node 2's previous access " + nodeTwo.prev.data;

document.querySelector('#nodeTwo').innerHTML = "Getting value through double preving node 4 " + nodeFour.prev.prev.data;

document.querySelector('#nodeThree').innerHTML = "Getting value through double nexting from node 1 " + nodeOne.next.next.data;

document.querySelector('#nodeFour').innerHTML = "Getting value through triple nexting from one " + nodeOne.next.next.next.data;

document.querySelector('#isHead').innerHTML = `Node one ${nodeOne.head ? ' is ': ' is not '} the head.`;

document.querySelector('#isTail').innerHTML = `Node three ${nodeThree.tail ? ' is ' : ' is not '} the tail, and Node 4 ${nodeFour.tail ? ' is ' : ' is not '} the tail.`