New to JS, please be nice.
In creating a Javascript score for a browser canvas game, the code below increases by 1 for each second. For the variable score to equal 100, how would I go about this function displaying a window alert for when it reaches this value?
Attempts similar to if(score == 100); alert(score) have not worked for me.
Below code will not currently work in JSFiddle, output displays in browser tab.
var start = new Date().getTime(),
score = '0.1';
window.setInterval(function() {
var time = new Date().getTime() - start;
score = Math.floor(time / 1000) ;
if(Math.round(score) == score)
{ score += '.0 Score'; }
document.title = score;
}, 100);
You might want to clear the interval when you are done. Otherwise the interval continues on executing and very soon the score is no longer 100 (or whatever the upper limit will be)
Something along the lines of:
var start = new Date().getTime(),
score = '0.1';
// get handle to interval function
var interval = window.setInterval(function() {
var time = new Date().getTime() - start;
score = Math.floor(time / 1000);
console.log(score);
if (score >= 5) { // set to 5 for speedier test/check
score += '.0 Score';
window.clearInterval(interval); // clear interval to stop checking
alert(score);
}
document.getElementById('title').innerHTML = score; // display it
document.title = score;
}, 100);
<div id="title"></div>
Related
So, I have a setInterval and a setTimeout running simultaneously in this click-o-meter thing I'm doing: the user enters an specified number of seconds he/she wants the game to run for, and then it counts how many clicks you have done, what was the average time between each click, and the average amount of clicks per second you've made during the specified period of time.
<html>
<head></head>
<body>
<input type='text' id='timerInput'></input>
<button id='btn'>Click</button>
<script>
var before;
var now;
var clicks = 0;
var cts = 0; //Stands for 'Clicks This Second'
var intervals = new Array();
var cps = new Array();
var cpsCounter;
var timer;
var canContinue = true;
var timerInput = document.getElementById('timerInput');
var timerTime;
var wasBad = false;
document.getElementById('btn').onclick = function() {
if(canContinue) {
if(clicks <= 0) {
if(timerInput.value.replace(/\D/, '') === timerInput.value) {
wasBad = false;
timerTime = parseInt(timerInput.value.replace(/\D/, '')) * 1000;
before = new Date();
cpsCounter = window.setInterval(ctsFunction, 1000);
timer = window.setTimeout(finish, timerTime);
}else{
alert('Only numbers please!');
wasBad = true;
}
}else{
now = new Date();
console.log(now - before);
intervals.push(now - before);
before = new Date();
}
if(!wasBad){
clicks++;
cts++;
}
}else{console.log('Game ended');}
};
function ctsFunction() {
console.log('Clicks this second: ' + cts);
cps.push(cts);
cts = 0;
}
function finish() {
console.log('Clicks: ' + clicks);
console.log('Average Speed (ms): ' + Math.floor(intervals.reduce(function(a, b){return a + b;}) / (clicks - 1)));
console.log('Average Speed (clicks per second): ' + (cps.reduce(function(a, b){return a + b;}) / cps.length));
intervals = new Array();
console.log('cps.length: ' + cps.length);
cps = new Array();
clicks = 0;
cts = 0;
window.clearInterval(cpsCounter);
canContinue = false;
}
</script>
</body>
</html>
So, the problem is that when the gmae finishes, that is, when timer reaches the end, ctsFunction() is supposed to run once more at the last second, so it can register data from it; but finish() is executed faster, or prior to ctsFunction(), thus clearing the cpsCounter interval and not allowing it to do anything on the last second. I've tried adding some extra milliseconds to timer, but if you choose to run the game for enough seconds, the same problem will eventually happen (e.g. if you add 1ms, the problem will be solved for up to 2 seconds, but not for more).
I have a setInterval and a setTimeout running simultaneously
It will never happens because javascript is a single thread language. There is no matter what is in your code, javascript can't execute two commands simultaneously.
And one more:
timer delay is not guaranteed. JavaScript in a browser executes on a
single thread asynchronous events (such as mouse clicks and timers)
are only run when there’s been an opening in the execution.
Read this article to understand how javascript timers work.
Well,
I Have a countdown timer, and I'm facing the following problem:
My countdown starts at 90 seconds. If the user waits until it reaches 2 seconds, for example, then he goes back using browser's button and after goes forward (backing to the same page), the countdown restarts at 90 seconds, not at 2 as I need, because when the timer reaches 0 I "click" at a button which post the form.
I know I need to handle the back and forward button and set my variable with the new value but I don't have any idea how can I do it. Any help will be great.
My code is below:
var count = 90;
var screenCount = count;
var newCount = 0;
function countFunction() {
if (screenCount != 0) {
var minutes = Math.floor(count / 60);
var seconds = count - minutes * 60;
if (count > 60){
if (seconds < 10)
seconds = "0" + seconds;
screen = minutes + "m:" + seconds + "s";
$('.timer').css('width',"120px")
}
else{
if (count < 10)
screen = "0" + count;
else
screen = count + "s";
$('.timer').css('width',"60px")
}
document.getElementById('tempo').innerHTML = screen;
if (count == 0) {
set('temporizador', screenCount);
$(":submit").removeAttr("disabled");
$('#responder').click();
}
if (count != 0) {
set('temporizador',screenCount - count );
count = count - 1;
setTimeout("countFunction()", 1000);
}
}
else {
document.getElementById('tempo').innerHTML = '∞';
set('temporizador', newCount);
newCount++;
setTimeout("countFunction()", 1000);
}
}
When the user presses back a whole new page is loaded, with an entirely new Javascript context. If you want to pass information from the context of one page to the context of another, there are several ways to do it.
In your particular situation, using LocalStorage is the easiest:
// count down 90 seconds, including page navigation on this site
var count = +localStorage.getItem('timerCount') || 90;
function countDown() {
count--;
localStorage.setItem('timerCount', count);
if (count<0) window.clearInterval(myInterval);
}
var myInterval = window.setInterval(countDown, 1000);
Suggestion by #DmitryVolokh
In this example i stored the remaining time in localStorage. If you want to track the elapsed time from a particular moment, you would be better served to store the starting time instead and compute the difference.
You use local storage for this as suggested above but there is the slight issue that some older browsers don't support localStorage: http://caniuse.com/#search=local%20storage
Since you are only storing a single number you could also use a cookie:
var match, count;
if (match = /timerCount=(\d+);/.exec(document.cookie)) {
count = match[1];
} else {
count = 90
}
function countDown() {
count--;
document.cookie = 'timerCount=' + count + ';';
if (count<0) window.clearInterval(myInterval);
}
var myInterval = window.setInterval(countDown, 1000);
You can use the onbeforeunload javascript event to see when the users leave the page, and then act as you want : changing the window.location to redirect the user (and give additional parameters like your timer), or prevent him from leaving the page.
You can also create a cookie or use localstorage to store the timer and get it back next time user comes to your page.
Forgive me if this sounds a little confusing ... I am trying to adjust the value of a progress bar based on my randomize variable.
var randomize = Math.round(Math.random() * (3000 - 2000) + 1000);
How do I then get javascript to count from 0 to 'randomize' in seconds, so that I can apply it to my progress bar?
You could do something like this:
var randomize = Math.round(Math.random() * (3000 - 2000) + 1000);
var counter = 0;
var timer = setInterval( function(){
if ( counter <= randomize ){
// update progress bar
counter += 1;
}else{
clearInterval( timer );
}
}, 1000 );
Basically what I'm doing here is setting up a function to be called every second ( 1000 = 1 second in JavaScript). The timer will check if the counter variable has reached the value of randomize and if not, it will increment it's value by one.
Once counter is equal to randomize, the timer will be cleared.
References -
setInterval()
clearInterval()
var seconds = 0;
var timer = setInterval(function() {
seconds = seconds + 1;
if (seconds == randomize) {
clearInterval(timer);
}
}, 1000);
I am developing a game in Metro app where there would be an initial timer for the game to run, let's say about 1 minute and 50 seconds and the timer is displaying the current time. if the 1 minute and 50 seconds time is over, the game will be over it will show a message, How would I implement such behaviour?
I would say, you can try this (untested):
remainingTime = 110;
setInterval(function() {
countdownStarted(); // game started
},
milliseconds // game will start in this much time
);
function countdownStarted() {
setInterval(function() {
remainingTime = remainingTime*100;
updateTimeOnScreen(); // after every second
if(remainingTime) countdownStarted();
},
100
);
}
function updateTimeOnScreen() {
if(remainingTime == 0) {
timeUp(); // game over
}
// function continues
}
For more examples, I would suggest you to read this article.
This basically does the trick, though this is the only thing my app does, so your real performance might vary and there are likely other improvements, stylistic and otherwise, you can make:
var timer = setInterval(function () {
var div = document.getElementById('time'); // this is just a div
// the div shows the time like this: "1:20" - 1 minute, 20 seconds
var lastValue = div.innerText.split(':');
var newValue = parseInt(lastValue[0]) * 60 + parseInt(lastValue[1]) + 1;
if (newValue === 110) {
div.innerText = "Game over!";
clearInterval(timer);
} else {
div.innerText = Math.floor(newValue / 60) + ':' + newValue % 60;
}
}, 1000);
For something more robust, check out this article. It looks like it's pretty close to what you want to do.
You can create an object that has a setTimeout and clearTimeout methods set to some user-defined value.
This link can also give you some useful info.
I am working on a simple game right now. its almost done except for the timer has a glitch in it and I can't figure out whats doing it. when you push a button, an HTML5 text on the canvas starts to count down from 35 to 0. On the first run it's fine. But if you choose to play again with out refresh the timer starts to countdown faster. here is the code.
var timer = 35;
ctx.fillText("Countdown: " + timer, 320, 32);
function resetReggie(){
reggie.x = canvasWidth / 2;
reggie.y = canvasHeight / 2;
}
//Starts Timer for Timed Game
function timedMsg()
{
resetReggie();
ballsCaught = 0;
timer = 35;
alert('Pick up as many as you can in ' + timer + ' seconds');
countDown();
var t=setTimeout(function() {
var again = confirm("TIMES UP! You Gathered " + ballsCaught + " Balls! Play Again?");
if (again === true){
timedMsg();
resetReggie();
}
if (again === false){
resetReggie();
ballsCaught = 0;
timer = 35;
}
}, timer * 1000);
}
function countDown() {
if (timer != 0){
timer-=1;
setTimeout('countDown()', 1000);
}
}
I think the problem is in the line
}, timer * 1000);
where you have a value that is at most 34 at the time 'timer' is evaluated to set the timeout. Because you initialize it to 35 but then call countDown() which decreases it to 34, then you have a call to confirm() which might let 'timer' decrease even more. As a result the subsequent call to timedMsg() happens a little too soon causing countDown() to be called twice as often. Try the following (I ran it in node) and then change the 4 to 6.
function countDown() {
console.log("Countdown: " + timer, 320, 32);
if (timer != 0) {
timer -= 1;
setTimeout(countDown, 1000);
}
}
function timedMsg() {
timer = 5;
countDown();
var t=setTimeout(function() {
timedMsg();
}, 4 * 1000);
}
timedMsg();
As mentioned in my comment, each time you start a new game, it appears you are decreasing the timeout value. As a result, this reduces the time each time.
Try this:
var timeout = currentTime = 5;
var int = setInterval(function() {
console.log(currentTime);
currentTime--;
if(currentTime < 0) {
var again = confirm('Play again?');
if(again) {
currentTime = timeout;
}
else {
clearInterval(int);
}
}
}, 1000);
http://jsfiddle.net/gRoberts/CsyYx/
Look at your console (F12 in Chrome), or update the code to write to the browser to see it working ;)