Old friend (and clearly damaged by a career of JavaScript programming) @jakedevine threw this down on twitter a few days ago.

    var Z = "constructor"; 
    Z[Z][Z]("alert('wtfjs!')")();
    // alerts wtfjs!

Ok. So wtf exactly is happening here?

    Z[Z]
    // function String() { [native code] }

    Z[Z][Z]
    // function Function() { [native code] }

AHA! The constructor property of a string is String and the constructor property of String is Function. Makes sense.

    Z[Z][Z]("console.log('new Function accepts string for eval as argument')")();
    // new Function accepts string for eval as argument

Of course. One wonders, as usual, wtf the programmer was up to when he discovered this!

--- @brianleroux

Void is a blackhole...

    var void = function () {}
    //=> SyntaxError: missing variable name

-- @rwaldron

When you create instances of String or Number, they take the default value ("" for strings and 0 for numbers). This is not the same for Object and Array.

    var a = new Number;
    a == 0 // true

    var a = new String;
    a == "" // true

    var a = new Object;
    a == {} // false

    var a = new Array;
    a == [] // false

This is even more confusing when using the JSON-style syntax to create objects and arrays.

    var a = {};
    a == {} // false

    var a = [];
    a == [] // false

-- @remi

(Never forget: ==== - @brianleroux)

This is much more awesome. I have to thank the guys at HowToNode.org for the idea in thier WheatJS static site blog engine. Essentially, it all boils down to running the rather awesome Google Code Prettyfy serverside.

The only remaining problem with the syntax highlighting is now nested <code> elements have to be escaped to display correctly in the final render.

    // replace the raw code blocks with prettyfied html
    t = t.replace(/<code>[^<]+<\/code>/g, function(code) {
        return prettyfy(code.match(/<code>([\s\S]+)<\/code>/)[1]);
    });    

Perhaps, in the future, a quick routine to fetch only the root code elements rather than blinding fetching all of them. Problem: more solved than before!

So, null is not an object though sometimes null is a Number.

    isNaN( null ); // false
    null === NaN; // false
    null == NaN; // false

isNaN converts null to number.

  Number( null ); // 0

But WTF. :) - @oleg008