JavaScript implementation of cons, car and cdr

ConsCarCdr.js

/**
  * Generic Container, which can contain a single item, and the next item as a function
  */
function cons(value, next) {
  return function wrap(wrapper) { return wrapper(value, next) };
};

/**
  * Get value of item by calling unwrap function, taking value
  */
function car(unwrap) {
  return unwrap(function(value, next) { return value });
};

/**
  * Get value of next by calling unwrap function, taking next
  */
function cdr(unwrap) {
  return unwrap(function(value, next) { return next });
};

var list = cons(1, cons(2, null));

// Why are they not using console.log?
document.writeln( car(list));
document.writeln( car(cdr(list)));
document.writeln( cdr(cdr(list)));
document.writeln( car(cdr(cdr(list))));