If you have a look with a tool like Chrome's Developer Tools, you'll see that the starting time is sent along each time you navigate to the next question, using POST:
Form Data
starttime: 1/6/2012 7:02:31 AM
answers: 00000000000000000000
qnumber: 2
The server interprets this data and most probably does something like (now - starttime).toMinutes() (pseudocode) to display the time spent. This also works when reloading the page, because time doesn't stop - (now - starttime) will obviously always give the correct result when the page is being built on the server.
It doesn't use JavaScript for this, so alerts don't pause anything - it's just a simple calculation on each page load.
I would imagine if it is not updating in real time, then it is probably not a timer, but more likely just a storage of the time you started, and then some calculations every so often of the time elapsed.
Change the Line
var mins = Math.floor((remaining % 1000 * 60 * 60)) / (1000 * 60));
to this
var mins = Math.floor((remaining % (1000 * 60 * 60)) / (1000 * 60));
and it will work
If you copy the whole code strait from the website, and paste it into your HTML document , It SHOULD WORK. IF THAT DOESN'T WORK, then don't name your file "index.html" sometimes files may override
I have two demos, one with jQuery and one without. Neither use date functions and are about as simple as it gets.
Demo with vanilla JavaScript (version with a start/stop button here)
function startTimer(duration, display) {
var timer = duration, minutes, seconds;
setInterval(function () {
minutes = parseInt(timer / 60, 10);
seconds = parseInt(timer % 60, 10);
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.textContent = minutes + ":" + seconds;
if (--timer < 0) {
timer = duration;
}
}, 1000);
}
window.onload = function () {
var fiveMinutes = 60 * 5,
display = document.querySelector('#time');
startTimer(fiveMinutes, display);
};<body>
<div>Registration closes in <span id="time">05:00</span> minutes!</div>
</body>Demo with jQuery (version with a start/stop button here)
function startTimer(duration, display) {
var timer = duration, minutes, seconds;
setInterval(function () {
minutes = parseInt(timer / 60, 10);
seconds = parseInt(timer % 60, 10);
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.text(minutes + ":" + seconds);
if (--timer < 0) {
timer = duration;
}
}, 1000);
}
jQuery(function ($) {
var fiveMinutes = 60 * 5,
display = $('#time');
startTimer(fiveMinutes, display);
});
However if you want a more accurate timer that is only slightly more complicated: (version with a start/stop button here)
function startTimer(duration, display) {
var start = Date.now(),
diff,
minutes,
seconds;
function timer() {
// get the number of seconds that have elapsed since
// startTimer() was called
diff = duration - (((Date.now() - start) / 1000) | 0);
// does the same job as parseInt truncates the float
minutes = (diff / 60) | 0;
seconds = (diff % 60) | 0;
minutes = minutes < 10 ? "0" + minutes : minutes;
seconds = seconds < 10 ? "0" + seconds : seconds;
display.textContent = minutes + ":" + seconds;
if (diff <= 0) {
// add one second so that the count down starts at the full duration
// example 05:00 not 04:59
start = Date.now() + 1000;
}
};
// we don't want to wait a full second before the timer starts
timer();
setInterval(timer, 1000);
}
window.onload = function () {
var fiveMinutes = 60 * 5,
display = document.querySelector('#time');
startTimer(fiveMinutes, display);
};<body>
<div>Registration closes in <span id="time"></span> minutes!</div>
</body>Now that we have made a few pretty simple timers we can start to think about re-usability and separating concerns. We can do this by asking "what should a count down timer do?"
- Should a count down timer count down? Yes
- Should a count down timer know how to display itself on the DOM? No
- Should a count down timer know to restart itself when it reaches 0? No
- Should a count down timer provide a way for a client to access how much time is left? Yes
So with these things in mind lets write a better (but still very simple) CountDownTimer
function CountDownTimer(duration, granularity) {
this.duration = duration;
this.granularity = granularity || 1000;
this.tickFtns = [];
this.running = false;
}
CountDownTimer.prototype.start = function() {
if (this.running) {
return;
}
this.running = true;
var start = Date.now(),
that = this,
diff, obj;
(function timer() {
diff = that.duration - (((Date.now() - start) / 1000) | 0);
if (diff > 0) {
setTimeout(timer, that.granularity);
} else {
diff = 0;
that.running = false;
}
obj = CountDownTimer.parse(diff);
that.tickFtns.forEach(function(ftn) {
ftn.call(this, obj.minutes, obj.seconds);
}, that);
}());
};
CountDownTimer.prototype.onTick = function(ftn) {
if (typeof ftn === 'function') {
this.tickFtns.push(ftn);
}
return this;
};
CountDownTimer.prototype.expired = function() {
return !this.running;
};
CountDownTimer.parse = function(seconds) {
return {
'minutes': (seconds / 60) | 0,
'seconds': (seconds % 60) | 0
};
};
So why is this implementation better than the others? Here are some examples of what you can do with it. Note that all but the first example can't be achieved by the startTimer functions.
An example that displays the time in XX:XX format and restarts after reaching 00:00
An example that displays the time in two different formats
An example that has two different timers and only one restarts
An example that starts the count down timer when a button is pressed
You can easily create a timer functionality by using setInterval() function. Below is the code which you can use it to create the timer.
http://jsfiddle.net/ayyadurai/GXzhZ/1/
window.onload = function() {
var minute = 5;
var sec = 60;
setInterval(function() {
document.getElementById("timer").innerHTML = minute + ":" + sec;
sec--;
if (sec == 00) {
minute--;
sec = 60;
if (minute == 0) {
minute = 5;
}
}
}, 1000);
}Registration closes in <span id="timer">5:00</span>!