How Do You Build "classes" In JavaScript?

I've generally built a JavaScript file for each "class" I want to build. So, each class would look something like:

Person.js

Code:

function Person()
{
var self = this;

// variables
this.XmlRequestPerson;

// methods
this.loginPerson = loginPerson;

function loginPerson(userName, password)
{
// do some stuff!
}
}

Having a class like this gives me the opportunity to do something like:

Code:

var person = new Person();
person.loginPerson("sup", "dude");

Are there better ways to do this? It just seems like the "var self = this" thing is stupid, because inside the Person.js file I have to reference everything local by "self" instead of "this".