Improve the string serialization output of Error objects using `.stack`, if it's available (recent Chrome and Firefox do!)

f1.js

// hopefill to wrap the built-in Error.prototype.string() with an improved version
(function(){
    var errToString = Error.prototype.toString;

    Error.prototype.toString = function() {
        var stack;
        // some browsers track the much more useful `.stack`, so use it!
        if (this.stack) {
            // some print the name/message in .stack, some don't. normalize it.
            stack = (this.stack + "").replace(new RegExp(this.name + ": " + this.message + "\n"),"");
            return this.name + ": " + this.message + "\n" + stack;
        }
        // otherwise, just use whatever the built-in behavior is.
        else {
            return errToString.call(this);
        }
    };
})();

f2.js

function blah() {
    function foo() {
        var a = true;
        try { a(); }
        catch (err) {
            console.log(err); // outputs just the err object
            console.log(err+""); // forces err#toString to get nicer output
        }
    }
    foo();
}

blah();

f3.txt

// Chrome outputs:

TypeError {}

TypeError: boolean is not a function
    at foo (<anonymous>:23:15)
    at blah (<anonymous>:29:5)
    at <anonymous>:32:1




// Firefox outputs:

[object Error]

TypeError: a is not a function
foo@debugger eval code:22
blah@debugger eval code:28
@debugger eval code:31

http://wiki.ecmascript.org/doku.php?id=strawman:error_stack