Javascript Date now() method

Date.prototype.now = function() {
    return ((this.getHours() < 10)?"0":"") + this.getHours() + ":" + 
            ((this.getMinutes() < 10)?"0":"") + this.getMinutes() + ":" + 
            ((this.getSeconds() < 10)?"0":"") + this.getSeconds();
};

function play(tag) {
    document.getElementById(tag).play();
}