sample.js

var jarsec = new Jarsec("   123 ");

var x = jarsec.space().integer().many(Jarsec.space).run();
var y = jarsec.space().choice(Jarsec.character("01"), Jarsec.integer, Jarsec.return).run();

function spaces() {
    this.many(spaces);
    return this;
};

function frstThird() {
    var x = this.item().run();
    this.space();
    var y = this.item().run();
    this.returnVal( x + y );
    return this;
}