I created a stopwatch using JavaScript, and I'm trying to start/stop the timer by space key, but it doesn't stop but always became more faster. '''
var timer_start = "S";
var time;
document.body.onkeyup = function (e) {
if (e.keyCode == 32) {
time = setInterval(timer, 10);
if (timer_start == "S") {
timer_start = "F";
} else if (timer_start == "F") {
clearInterval(time);
timer_start = "S";
}
}
};
,,,
Once the spacebar is pressed, you are starting the timer again regardless of the current value of timer_start. You need to move this to be inside the if statement. I'd also recommend using a Boolean instead of the string "S" and "F".
Here is my proposed rewrite of your code:
var timer_start = true;
var time;
document.body.onkeyup = function (e) {
if (e.keyCode == 32) {
if (timer_start) {
time = setInterval(timer, 10);
timer_start = false;
} else {
clearInterval(time);
timer_start = true;
}
}
};
You could also shorten it a bit by doing this if you wanted
var timer_start = true;
var time;
document.body.onkeyup = function (e) {
if (e.keyCode == 32) {
if (timer_start) {
time = setInterval(timer, 10);
} else {
clearInterval(time);
}
timer_start = !timer_start
}
};
You set the interval regardless of the timer_start state, so you keep piling up new intervals and remove only half of them. You should set the interval only in the timer_start == "S" branch.