检查一下：
var minutesLabel = document.getElementById("minutes");var secondsLabel = document.getElementById("seconds");var totalSeconds = 0;setInterval(setTime, 1000);function setTime() { ++totalSeconds; secondsLabel.innerHTML = pad(totalSeconds % 60); minutesLabel.innerHTML = pad(parseInt(totalSeconds / 60));}function pad(val) { var valString = val + ""; if (valString.length < 2) { return "0" + valString; } else { return valString; }}<label id="minutes">00</label>:<label id="seconds">00</label>
