String.format = function () {
	var s = arguments[0];
	for (var i = 0; i < arguments.length - 1; i++) {
		var reg = new RegExp("\\{" + i + "\\}", "gm");
		s = s.replace(reg, arguments[i + 1]);
	}

	return s;
}

String.prototype.endsWith = function (suffix) {
	return (this.substr(this.length - suffix.length) === suffix);
}

String.prototype.startsWith = function (prefix) {
	return (this.substr(0, prefix.length) === prefix);
}