This is a simple exploration of the Google Closure Compiler's use of JSDoc and the @type's needed to validate the code.

jsdoc.js

/*

General notes:

Curly braces around the types seem to be optional. "{number}" works the same as
"number".

*/


/**
 * @type {boolean} bool
 */
var bool = true;

/**
 * @type {number} num
 */
var num = 1;

/**
 * @type {string} str
 */
var str = '';

/**
 * "null", "Null" and "Object" seem to work here.
 *
 * @type {null} nul
 */
var nul = null;

/**
 * @type {undefined} undef
 */
var undef = undefined;

/**
 * @type {Array} arr
 */
var arr = [];

/**
 * @type {Object} obj
 */
var obj = {};

/**
 * @type {RegExp} reg
 */
var reg = /a/;

/**
 * @type {Function} fn
 */
var fn = function () {};

/**
 * @type {Date} date
 */
var date = new Date();

/**
 * The constructor tag is needed or the "Foo" type will not be recognised.
 *
 * @constructor
 */
function Foo() {
}

/**
 * @type {Foo} foo
 */
var foo = new Foo();

/**
 * @type {Element} dom
 */
var dom = document.createElement('p');

/**
 * The asterisk denotes any type or "mixed"
 * 
 * @type {*} mixed
 */
var mixed = ['a', 1, {}, []][Math.floor(Math.random() * 4)];