JavaScript LinkedList

function LinkedList() {

var Node = function(element) {

this.element = element;

this.next = null

}

var length = 0;

var head = null;

this.append = function(element) {

var node = new Node(element),

current;

if (head == null) {

head = node

} else {

current = head;

while (current.next) {

current = current.next

}

current.next = node

}

length++

}

this.insert = function(position, element) {

if (position >= 0 && position <= length) {

var node = new Node(element),

current = head,

previous,

index = 0;

if (position == 0) {

node.next = current;

head = node

} else {

while (index++<position) {

previous = current;

current = current.next

}

node.next = current;

previous.next = node

}

length++;

return true

} else {

return false

}

}

this.removeAt = function(position) {

if (position > -1 && position < length) {

var current = head,

previous, index = 0;

if (position == 0) {

head = current.next

} else {

while (index++<position) {

previous = current;

current = current.next

}

previous.next = current.next

}

length--;

return current.element

} else {

return null

}

}

this.remove = function(element) {

var index = this.indexOf(element);

return this.removeAt(index)

}

this.indexOf = function(element) {

var current = head,

index = -1;

while (current) {

if (element == current.element) {

return index

}

index++;

current = current.next

}

return - 1

}

this.isEmpty = function() {

return length == 0

}

this.size = function() {

return length

}

this.getHead = function() {

return head

}

this.toString = function() {

var current = head,

string = '';

while (current.next) {

string = current.element;

current = current.next

}

return string

}

this.print = function() {}

}

var linkedList = new LinkedList();

linkedList.append("shidengyun");

linkedList.insert(0, 'zhujing');

console.log(linkedList.toString());