if (!String.prototype.format) {
    String.prototype.format = function() {
        var str = this.toString();
        if (!arguments.length)
            return str;
        var args = typeof arguments[0],
            args = (("string" == args || "number" == args) ? arguments : arguments[0]);
        for (var arg in args) {
            str = str.replace(RegExp("\\{" + arg + "\\}", "gi"), args[arg]);
        }
        return str;
    }
}