coinflip()

gistfile1.js

var results = { heads: 0, tails: 0, total: 0 };

function coinflip() {
	var heads = !!Math.round(Math.random());
	if (heads) {
		results.heads++;
	} else {
		results.tails++;
	};
	results.total++;
	console.log("Heads: " + Math.round(results.heads / results.total * 100) + "%; Tails: " + Math.round(results.tails / results.total * 100) + "%; Flips: " + results.total);
	if (results.total >= 100) { clearInterval(flipping); }
}

var flipping = setInterval(coinflip, 25);

// will stop at 100 flips. to stop manually...
// clearInterval(flipping);