Plain JS Countdown With Repeat And Delay

I keep running into several issues when creating a countdown script it does not run smoothly hard to make it repeat (closure) hard to delay the start and to delay the repeat (clos

Solution 1:

I've rewritten your code to produce the desired results. Your previous code was very inefficient. See my script comments for usage.

Fiddle: http://jsfiddle.net/RVBDQ/1/

/*
  @name  timer
  @param number startFrom     Starts counting down from this number
  @param number delay         Seconds to wait before repeating the counter
  @param number intervalDelay Milliseconds between countdown
  @param number runTimes      Optional; Limit of counting. The function stops when it has run <runTimes> times. Default 1 (=one countdown)
  @param Boolean noFirstRun   Optional; If false, the counter starts off immediately. Default false
*/

function timer(startFrom, delay, intervalDelay, runTimes, notFirstRun){
    if(typeof runTimes == "undefined") runTimes = 1;
    if(runTimes-- < 0) return;
    setTimeout(function(){
        var ctn = startFrom;
        var timer1 = window.setInterval(function(){
            document.getElementById('out1').innerHTML = ctn--;
            if(ctn <= 0){
                clearInterval(timer1);
                timer(startFrom, delay, intervalDelay, runTimes, true);
            }

        }, intervalDelay);
    }, notFirstRun?delay*1000:0);
}
window.onload=function() {
    timer(10, 5, 1000, 2);
    //Runs two times, starts counting from 10 to 1, delays 5 seconds between counters.
}  

Solution 2:

Object exposing start([delay]) and stop().

http://jsfiddle.net/RVBDQ/3/

function interval(duration, fn, delay){
    this.timer = null;
    this.duration = duration;
    this.fn = fn;

    this.start(delay);
}
interval.prototype.start = function(delay){
    if (this.timer) {return;}
    var self=this;
    this.timer = setTimeout(function(){ self.run(); }, delay||0);
};
interval.prototype.run = function(called){
    var self = this,
        nextTick = called ? this.duration - (new Date - called) : 0;

    this.timer = setTimeout(function(){
        self.fn();
        self.run(new Date);
    }, nextTick<0 ? 0 : nextTick);
};
interval.prototype.stop = function(){
    clearTimeout(this.timer);
    this.timer = null;
};

window.onload = function() {
    var cnt1 = 10;
    var delay1 = 5;
    window.timer1 = new interval(1000, function(){
        document.getElementById('out1').innerHTML=cnt1;
        cnt1 = cnt1 === 1 ? 10 : cnt1-1;
    }, delay1*1000);
};