Javascript string prototypes

string.js

String.prototype.format = function() {
    var ret = this;
    for (var i = 0; i < arguments.length; i++) {
        var rex = RegExp("\\{" + i + "\\}", "g");
        ret = ret.replace(rex, arguments[i]);
    }
    return ret;
}

String.prototype.q = function() {
    return "'" + this.replace("'", "''") + "'";
}