Why doesn't this simple JavaScript increment and decrement method work? - javascript

(function() {
var count = {
digit: 0,
increment: function() {
var interval = setInterval(function() {
if (++count.digit == 10) {
clearInterval(interval);
count.decrement();
}
var update = document.getElementById("liveUpdate");
update.innerHTML = count.digit;
}, 500);
},
decrement: function() {
var interval = setInterval(function() {
if (--count.digit == -1) {
clearInterval(interval);
}
}, 500);
}
};
count.increment();
})();
It stops but it doesn't go down? What could be the problem?

Your decrement function never updates the output anywhere. The variable is going down but you don't show that on screen.
Try (or check the corresponding JSFiddle):
(function() {
var update = document.getElementById("liveUpdate");
var count = {
digit: 0,
increment: function() {
var interval = setInterval(function() {
if (++count.digit == 10) {
clearInterval(interval);
count.decrement();
}
update.innerHTML = count.digit;
}, 500);
},
decrement: function() {
var interval = setInterval(function() {
if (--count.digit == -1) {
clearInterval(interval);
}
update.innerHTML = count.digit;
}, 500);
}
};
count.increment();
})();

setInterval will call the function every 500 seconds. It will not stop until you stop it. You can read more about stopping it at Stop setInterval call in JavaScript

It't not a bug, it's a feature ;-). setInterval() runs the given function in a loop with a given interval (500 ms). See this article for details.

Related

How to kill and restart the recursive function in javascript

I am working on knockout js.
In that i have a recursive function which executes a function every minute. for that am using a timer every 60 sec it will execute also same will be reflecting in the UI also.
In my case, if i try to assign or initialize a timer value(observable) which is inside a loop, it doesn't reflecting instead of reflecting it is added to the pipeline and that much time loop is running simultaneously.
In that case i want to kill the loop and again want to restart every time i am changing the timer value.
timerInSec=60;
var loop = function () {
if (this.timer() < 1) {
myFunction()
this.timer(this.timerInSec - 1);
setTimeout(loop, 1000);
} else {
this.timer(this.timer() - 1);
setTimeout(loop, 1000);
}
};
loop();
Here is my solution. Please check.
timerInSec = 60;
const Loop = (function () {
let timer = 0;
let timerId = -1;
const myFunction = function () {
console.log('finished');
}
const fnLog = function (tm) {
console.log('current time = ', tm);
}
const fnProc = function () {
timerId = setTimeout(myFunction, 1000 * timer);
}
return {
start: function (tm = 60) {
this.stop();
timer = tm;
fnProc();
},
stop: function () {
if (timerId !== -1) {
clearTimeout(timerId);
timerId = -1;
}
}
}
})();
Loop.start(timerInSec);
setTimeout(() => {
Loop.start(timerInSec);
}, 500);

hold down button after 1 second and loop the action using jQuery

I got this code from: Jquery: mousedown effect (while left click is held down)
It is behaving that if I am holding the button in every 50ms it will do something.
var timeout = 0;
$('#button_add').mousedown(function () {
timeout = setInterval(function () {
value_of_something ++;
}, 50);
return false;
});
});
But what I want is to execute this part after holding down the button by 1 second and it will continuously do the action 50ms.
As I said you need to use setTimeout()
var timeout = 0;
$('#button_add').mousedown(function () {
setTimeout(function(){
timeout = setInterval(function () {
value_of_something ++;
}, 50);
} , 1000);
return false;
});
Jsfiddle
Please use this code... You have to clearTimeout when user mouseup :
var timeout = 0;
$('#button_add').mousedown(function() {
oneSecondTimer = setTimeout(function() {
timeout = setInterval(function() {
value_of_something++;
}, 50);
}, 1000);
return false;
});
$("#button_add").mouseup(function() {
clearTimeout(oneSecondTimer);
});

clearinterval() outside of jquery plugin

I create plugin something like this
timer plugin
(function($) {
$.fn.timer = function(options) {
var defaults = {
seconds: 60
};
var options = $.extend(defaults, options);
return this.each(function() {
var seconds = options.seconds;
var $this = $(this);
var timerIntval;
var Timer = {
setTimer : function() {
clearInterval(timerIntval);
if(seconds <= 0) {
alert("timeout");
}else {
timerIntval = setInterval(function(){
return Timer.getTimer();
}, 1000);
}
},
getTimer : function () {
if (seconds <= 0) {
$this.html("0");
} else {
seconds--;
$this.html(seconds);
}
}
}
Timer.setTimer();
});
};
})(jQuery);
and I call the plugin like this.
$(".myTimer").timer({
seconds : 100
});
i called the plugin at timerpage.php. When i changed the page to xxx.php by clicking another menu, the timer interval is still running and i need to the clear the timer interval.
i created a webpage using jquery ajax load. so my page was not refreshing when i change to another menu.
my question is, how to clear the timer interval or destroy the plugin when i click another menu?
Please try with following modifications:
timer plugin:
(function($) {
$.fn.timer = function(options) {
var defaults = {
seconds: 60
};
var options = $.extend(defaults, options);
return this.each(function() {
var seconds = options.seconds;
var $this = $(this);
var timerIntval;
var Timer = {
setTimer : function() {
clearInterval(timerIntval);
if(seconds <= 0) {
alert("timeout");
}else {
timerIntval = setInterval(function(){
return Timer.setTimer();
}, 1000);
$this.data("timerIntvalReference", timerIntval); //saving the timer reference for future use
}
},
getTimer : function () {
if (seconds <= 0) {
$this.html("0");
} else {
seconds--;
$this.html(seconds);
}
}
}
Timer.setTimer();
});
};
})(jQuery);
Now in some other JS code which is going to change the div content
var intervalRef = $(".myTimer").data("timerIntvalReference"); //grab the interval reference
clearInterval(intervalRef); //clear the old interval reference
//code to change the div content on menu change
For clearing timer associated with multiple DOM element, you may check below code:
//iterate ovel all timer element:
$("h3[class^=timer]").each(function(){
var intervalRef = $(this).data("timerIntvalReference"); //grab the interval reference
clearInterval(intervalRef);
});
Hope this will give an idea to deal with this situation.
Instead of var timerIntval; set the variable timerInterval on the window object, then you will have the access this variable until the next refresh.
window.timerIntval = setInterval(function() {
Then when the user clicks on any item menu you can clear it:
$('menu a').click(function() {
clearInterval(window.timerIntval);
});
Live example (with multiple intervals)
$('menu a').click(function(e) {
e.preventDefault();
console.log(window.intervals);
for (var i = 0; i < window.intervals.length; i++) {
clearInterval(window.intervals[i]);
}
});
(function($) {
$.fn.timer = function(options) {
var defaults = {
seconds: 60
};
var options = $.extend(defaults, options);
return this.each(function() {
if (!window.intervals) {
window.intervals = [];
}
var intervalId = -1;
var seconds = options.seconds;
var $this = $(this);
var Timer = {
setTimer : function() {
clearInterval(intervalId);
if(seconds <= 0) {
alert("timeout");
} else {
intervalId = setInterval(function(){
//Timer.getTimer();
return Timer.getTimer();
}, 1000);
window.intervals.push(intervalId);
}
},
getTimer : function () {
if (seconds <= 0) {
$this.html("0");
} else {
seconds--;
$this.html(seconds);
}
}
}
Timer.setTimer();
});
};
})(jQuery);
$(".myTimer").timer({
seconds : 100
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<menu>
Menu 1
</menu>
<div class="myTimer"></div>
<div class="myTimer"></div>
Just notice that it's little bit risky because you can only run it once otherwise the interval id of the second will override the first.

clearInterval does not work

I'm trying to create a simple countdown timer. It counts down from the number entered.
However, I'm trying to clear the interval when the counter gets to 0. At the moment it seems to acknowledge the if statement, but not clearInterval().
http://jsfiddle.net/tmyie/cf3Hd/
$('.click').click(function () {
$('input').empty();
var rawAmount = $('input').val();
var cleanAmount = parseInt(rawAmount) + 1;
var timer = function () {
cleanAmount--;
if (cleanAmount == 0) {
clearInterval(timer);
}
$('p').text(cleanAmount);
};
setInterval(timer, 500);
})
You're not saving the return value of the call to setInterval, which is the value that needs to be passed to clearInterval. Passing the timer handler does no good.
var timer, timerHandler = function () {
cleanAmount--;
if (cleanAmount == 0) {
clearInterval(timer);
}
$('p').text(cleanAmount);
};
timer = setInterval(timerHandler, 500);

Resetting setinterval in JS

Code looks like that:
function startTimer(counter) {
var interval = setInterval(function () {
counter--;
$('#timer').html(counter);
// Display 'counter' wherever you want to display it.
if (counter == 0) {
clearInterval(interval);
$('#question').html("Time ended");
setTimeout(function () {
window.location.href = "/";
}, 5000);
return false;
}
}, 1000);
}
What I want to do is, when I call this function multiple times, every time to reset timer to 30 seconds and kill all past instances. Currently it messes up with past intances when I call multiple times. What am I doing wrong?
You have to define the var interval outside the function:
var interval;
function startTimer(counter) {
interval = setInterval(function () {
counter--;
$('#timer').html(counter);
// Display 'counter' wherever you want to display it.
if (counter == 0) {
clearInterval(interval);
$('#question').html("Time ended");
setTimeout(function () {
window.location.href = "/";
}, 5000);
return false;
}
}, 1000);
}

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