/**

 * @function 倒计时器

 * @author Kyle

 * @belog Kookjs

 * @time 2008-12-17

 * @version 1.0

 */

/**

 *

 * @param perMS 间隔时间

 * @param timeOut 过期时间

 * @param inFn   间隔执行函数

 * @param endFn  过期执行函数

 */

function TimerOut(perMS,timeOut,inFn,endFn) {

    this.perMS = perMS;

    this.timeOut = timeOut;

    this.currTime = perMS;

    this.interval = false;

    this.inFn = inFn;

    this.endFn = endFn;

}

TimerOut.prototype.perFn = function() {

    this.currTime += this.perMS;

    var currTime = this.currTime;

    var timeOut = this.timeOut;

    if (currTime > timeOut) {

        window.clearInterval(this.interval);

        this.endFn();

    } else {

        this.inFn(currTime);

    }

};

TimerOut.prototype.start = function() {

    var thisp = this;

    this.interval = window.setInterval(function() {

        thisp.perFn();

    }, this.perMS);

};

//测试

//测试

var timer = new TimerOut(1000, 3000, function() {

    alert(1)

}, function() {

    alert('end');

});

timer.start();

文章出处：DIY部落(http://www.diybl.com/course/4_webprogram/asp.net/netjs/20090318/163153.html)