String.prototype.upperLower = function () {
	var result = '',
		direction = 'up';

	for (var i = 0; i < this.length; i++) {
		if (direction == 'up') {
			result += this[i].toUpperCase();
		} else {
			result += this[i].toLowerCase();
		}

		if (this[i] !== ' ') {
			if (direction == 'up') {
				direction = 'down';
			} else {
				direction = 'up';
			}
		}
	}

	return result;
};


console.log('ala ma kota i lubi placki'.upperLower());