JavaScript setInterval函数不会停止

Question

I am new to javascript. I am checking a time period from my database and showing how much time left to the end of the period.

I got the time value with strtotime as a variable $lefttime in php. My problem is with javascript part so i am not writing the php codes.

So my javascript code is:

var s = <?php echo $lefttime; ?>; //s stands for seconds
var d = Math.floor(s/60);         //d stands for minutes
s -= d*60;

var count = setInterval(functime, 1000);
    function functime() {
        s--;

        if(s < 0) {
            d--;
            s = 59;                 
            var san = s;
            var dak = "0" + d;   
        }
        else if(d < 0 ) {
                clearInterval(functime);
                document.getElementById('id').innerHTML = "over";
            }
        else if(d < 10){
            var dak = "0" + d;
            if(s < 10) { 
                       var san = "0" + s;
                    }
            else { 
                       var san = s; 
                    }
        }
        else if(s < 10){
            var san = "0" + s;
            if(d < 10) { 
                       var dak = "0" + d;
                    }
            else { 
                       var dak = d; 
                    }
        }
        else { 
            var san = s;
            var dak = d;
        }

        document.getElementById('id').innerHTML = dak+":"+san;
    }

I create dak and san variables to check if the value is a digit, if so add 0 to the left of them.

So it works perfect except stopping when d < 0 . It counts down till 00:00 and then shows 0-1:59 , and then undefined:undefined .

Please help me I can't find what is wrong.

Answer 1

setInterval returns an identifier for the interval

var myInterval = setInterval(functime, 1000);

And it's this numeric identifier that should be passed as a parameter to clearInterval

clearInterval(myInterval);

update: You code is much too complex. You have too many nested if/else, so it makes it complicated to understand. You should create several simple functions to isolate small chunks of code with a specific responsibility. By example:

var s = <?php echo $lefttime; ?>; //s stands for seconds
var d = Math.floor(s/60);         //d stands for minutes
s -= d * 60;

update(d, s);
if(d >= 0) {
    var myInterval = setInterval(functime, 1000);
} 
else {
    finish();
}

function functime() {
    s--;
    if(s < 0 ) {
        d--;
        if (d < 0 ) {
            clearInterval(myInterval);
            finish();
            return;
        }
        else {
            s = 59;
        }
    }
    update(d, s);   
}

function format(value) {
    if(value < 10) {
        return '0' + value;
    }
    return value;
}

function update(d, s) {
    var san = format(s);
    var dak = format(d);
    document.getElementById('id').innerHTML = dak + ":" + san;
}

function finish() {
    document.getElementById('id').innerHTML = "over";
}