Develop Reference

How to approach a setInterval triggering a setInterval within the same function

I a rewards site. Users earn points when they watch videos. Users want to skip to the end of the video to quickly earn their points. Therefore, the mechanism of the video being marked as completed is managed by a JS timer.
The Problem: When a user pauses the video, the timer needs to pause. When the user clicks play again, a setInterval is used to reopen the function, where a setInterval within the existing function does the same thing, creating a huge problem...
This is the code that is set every second to update the timer...
var video_percent_count = 0;
function video_percent() {
var prize_video = document.getElementById("prize_video");
total_duration = Math.floor(prize_video.duration) + 1;
video_percent_count++;
percent = video_percent_count / total_duration;
convert_percent = (percent * 100).toFixed(2);
if(convert_percent == 100) {
clearInterval(video_percent_interval);
}
if(prize_video.paused) {
clearInterval(video_percent_interval);
}
if(prize_video.play) {
setInterval("video_percent()", 1000);
}
$(".percent_container").text(convert_percent);
}
function prize_video(count_prize) {
var back_count_prize = count_prize - 1;
$("#prize_video").get(back_count_prize).play();
video_percent_interval = setInterval("video_percent()", 1000);
}
How can I properly manage play and pause and still keep setInterval clean?

Using javascript/jQuery, wait 3 seconds for click, then proceed

I've been trying to figure out how to run an infinite loop while pausing for user click, then allow for a break out.
When the loop starts, the user is presented with an image, and must choose the identical image from one of 4 displayed. If they successfully click the match within 5 seconds, they are presented another image, and the game goes on.
If they either choose an incorrect image, or 5 seconds elapses, the game ends.
I've got all of the functionality worked out, except this pause while waiting for a click or the time to expire.
Ideally, I'd also like the time to be adjustable on each iteration. Say start at 5 seconds, then shorten the time slightly (10ms) on each loop.
I believe it must be solvable using setTimeout() or setInterval(), but just can't wrap my head around it.
Here is a minimal concept of what I'm trying to accomplish.
$('#playnow').on('click',function(){
var speed = 5000;
var speed_reduce = 10;
var game_running = true;
/* create array of images */
var imgs = ['puppy.png','kitten.png','bunny.png','goldfish.png'];
var runnow = setInterval(
function(){
//get random image from loaded theme
rand_img = imgs[Math.floor(Math.random() * imgs.length) ];
//display chosen image
$('#goal_image').html('<img src="'+theme_dir+rand_img+'" />');
// wait up to 5 seconds for user to click or time to expire
if(*clicked and matched*){
//get new random image and reset timer (less 10ms)
}
if(*time expired*){
//bail out and game ends
}
/* reduce time */
speed -= speed_reduce;
},
speed);
});

You'll want something like this I think:
var speed = 5000, // the initial time
currentimage,
timer,
gamerunning;
function newimage(){
var imgs = ['puppy.png','kitten.png','bunny.png','goldfish.png'];
currentimage=Math.floor(Math.random() * imgs.length);
$('#goal_image').html('<img src="'+theme_dir+imgs[currentimage]+'" />');
timer = setTimeout(speed, lost)
}
function answer(id){
if(!gamerunning){return}
clearTimeout(timer)
if(id==currentimage){
speed -= 10; // time decrease every time.
newimage();
}else{
lost()
}
}
function lost(){
gamerunning=0;
speed=5000;
// what to do when lost.
}
$("#puppy").on("click",function(){answer(0)}); // here #puppy is the id of the answer image, and 0 the index in the imgs array.
$("#kitten").on("click",function(){answer(1)});
$("#bunny").on("click",function(){answer(2)});
$("#fish").on("click",function(){answer(3)});
$("#gamestartbutton").on("click",function(){gamerunning=1})

One way to solve this problem is to use setTimeout() and clearTimeout() rather than setInterval. Also, you need some event for the successful button click (I've pretended you have a special "#successfulmatch" button):
var speed = 5000;
var speed_reduce = 10;
var game_running = true;
var imgs = ['puppy.png','kitten.png','bunny.png','goldfish.png'];
var myTimeout;
function runNow(speed){
rand_img = imgs[Math.floor(Math.random() * imgs.length) ];
$('#goal_image').html('<img src="'+theme_dir+rand_img+'" />');
// Keep track of the timeout so we can cancel it later if the user clicks fast enough.
myTimeout = window.setTimeout(function(){
game_running = false;
gameEnds();
},speed);
}
$('#successfulmatch').on('click',function(){
if(game_running){
// Cancel the timeout because the user was fast enough
window.clearTimeout(myTimeout);
// Give the user less time than before
runNow(speed - speed_reduce);
}
else{
// Throw an error: you forgot to hide the clickable buttons when the game ended.
}
}
$('#playnow').on('click',function(){
runNow(speed);
}

Looks like you are mixing the logic for checking "has the user clicked the image? was it correct?" with the one for checking "has time expired?"
You can listen for onclick events on the images
and set a timeout event for the game over
so the user has to cancel that timer, to cancel imminent game over, by clicking on the images
if the right image is clicked the timer is reset
if not, it's game over
you can cancel a timeout event before it runs with cancelTimeout()
see W3C here for a reference.
here is a quick prototype:
$('#playnow').on('click', function() {
var speed = 5000;
var speed_reduce = 10;
var game_running = true;
/* create array of images */
var imgs = ['puppy.png', 'kitten.png', 'bunny.png', 'goldfish.png'];
// function that ends the game if it's called
function gameover() {
alert("GAME OVER");
game_running = false;
}
// in order to use clearTimeout() you must store the timer in a global variable
// setting a timeout that will end the game if it's not cleared before
window.timer = setTimeout(gameover, speed);
// function that is called whenever the user clicks on a image
function onclickimage(event) {
if (!game_running) return;
if ( /*clicked right img*/ ) {
// get random image from loaded theme
var rand_img = imgs[Math.floor(Math.random() * imgs.length)];
// display chosen image
$('#goal_image').html('<img src="' + theme_dir + rand_img + '" />');
// delete timer, user now has one more opportunity
clearTimeout(timer);
// speed is less 10ms
speed -= speed_reduce;
// launch timer again
window.gametimer = setTimeout(loop, speed);
} else { // if click did not match correct image
gameover();
}
}
});

Well, firstly, you need to clearInterval() when they either click or fail in order to stop the current interval. Then, you can restart an interval with the new speed. The interval seems to be working for.
Every 5 seconds a new picture is displayed. So, you want an onclick event for the picture that clears the interval and starts a new one. So, you may want to use setTimeout instead of setInterval since it is only a single iteration at a time.
You could use setInterval, I suppose, but there's no real benefit to it. This way also makes it relatively easy to reduce the speed each time.

My script for page loading bar, returns differently everytime of F5

I got a free source progress bar, and I wrote a script for it.
the script is here,
var nanobar = new Nanobar( options );
var loaded = 0;
var number_of_media = $("body img").length;
doProgress();
// function for the progress bar
function doProgress() {
$("img").load(function() {
loaded++;
var newWidthPercentage = (loaded / number_of_media) * 100;
nanobar.go(newWidthPercentage);
document.getElementById("showing").innerHTML = newWidthPercentage;
})
};
});
This. I think,
Loaded <-- (which gets + 1 every time an image finished loaded)
divided by
Number of total body images,,
and then multiplied by 100
So that this can make the percentage number of loading process.
Then I put that percentage number into the box of,
A Loading bar's destination point. (which is : nanobar.go( here ))
But the bar moves werid,
everytime I click the menu, it returns different.
so I made a box to display the percentage number ( in the red box you can see in the picture )
I don't understand how this kind of random numbers are coming out every time.
Please advice.

Consider....
6/7 = 0.8571428571;
0.8571428571 * 100 = 85.71428571;
So if you want to 'tidy' these long decimals, then you need to truncate the float. http://www.w3schools.com/jsref/jsref_tofixed.asp
var num = 0.8571428571 * 100;
var n = num.toFixed(2);
Then n == 85.71
I hope this helps.

setInterval does not stop after second call

I am currently working on a battle system.
The health gets calculated every 200ms, and I'm using a Interval. It works pretty good, until I start the game - the Interval again. It doesn't stop anymore.
It is a lot of code - I have also an online live demo here http://wernersbacher.de/pro/coinerdev/
Like I said - works the first, but not the second.
So, just the main code:
var frameStop;
// Draws Startscreen
function showStartRaid(name) {
playerBTC = btc;
playerBTCs = btcs;
playerName = nick;
// Sets stats for called level
enemyBTC = dun[name]["buyer"]["btc"];
enemyBTCs = dun[name]["buyer"]["btcs"];
enemyName = dun[name]["buyer"]["label"];
enemyNum = dun[name]["meta"]["base"];
/* Reset everything in html */
}
var battle = false;
$(".raid_building").click(function() {
//Draws level
showStartRaid(name);
//Sets start BTC as fighting stats (they will decrease during battle)
fplayerBTC = playerBTC;
fenemyBTC = enemyBTC;
//Click on "Start"
$("#startRaid").click(function() {
function raiden() {
//Calculates fighting
fenemyBTC -= playerBTCs/frameMinus;
fplayerBTC -= enemyBTCs/frameMinus;
/*Draws stats and health here in html */
if(fplayerBTC >= 0 && fenemyBTC >= 0)
console.log("battle goes on")
else {
//If battle is over, stop it
clearInterval(frameStop);
}
}
//Start battle
frameStop = setInterval(raiden, frameRaid);
});
});
Thanks for any help, I'm helpless.

With your code, every time .raid_building is clicked, you hook up a new handler for clicks on #startRaid. So that means, if .raid_building is clicked twice, you'll have two handlers for clicks on #startRaid, both of which start a new interval timer. Your frameStop variable will only contain the handle of one of them; the other will continue. And of course, a third click will compound the problem (you'll have three click handlers, each of which fires up a new interval timer). And so on...
Move the code hooking click on #startRaid outside the click handler on .raid_building.

JQuery progress bar pauses when browser tab is changed

I'm trying to display a progress bar on a html page using javascript. However,
when the browser tab containing the code becomes inactive, the progress bar stops updating,
being resumed when the tab is active again.
How can I prevent the browser from stopping/pausing the execution of javascript code when the window is inactive?
Although it may be irrelevant, here is the code:
Object.progressBar = function(){
$( "#question-progress-bar" ).progressbar({
value: false,
complete: function(event, ui) { ... }
});
var seconds = 15.0,
progressbar = $("#question-progress-bar"),
progressbarValue = progressbar.find(".ui-progressbar-value");
progressbarValue.css({
"background": '#c5b100',
"opacity" : '0.8'
})
var int = setInterval(function() {
var percent = (15-seconds)/15*100;
seconds=seconds-0.1;
progressbar.progressbar( "option", {
value: Math.ceil(percent)
});
$("#question-progress-bar-seconds").html((seconds).toFixed(1)+"s");
if (seconds <= 0.1) {
clearInterval(int);
}
}, 100);
}

Instead of using setInterval and assuming a certain amount of time has passed between calls (even when it's up front, setInterval has hit or miss accuracy) use the Date object to get a time when the bar starts, and compare that to the current time at each iteration.
<html>
<head>
<script>
function go()
{
var pb = new ProgressBar(5, "targ");
}
window.onload = go;
function ProgressBar(l, t)
{
var start = Date.now();
var length = l * 1000;
var targ = document.getElementById(t);
var it = window.setInterval(interval, 10);
function interval()
{
var p = 100 * (Date.now() - start) / length;
if(p > 100)
{
p = 100;
window.clearInterval(it);
alert("DONE"); // alternatively send an AJAX request here to alert the server
}
targ.value = (Math.round(p) + "%");
}
}
</script>
</head>
<body>
<input type="text" id="targ" />
</body>
</html>
I've made an example object, here, that immediately starts a countdown when instantiated and calls an alert and kills the interval timer when done. Alternatively an AJAX call, or any other sort of call can be done upon completion.
It should be noted that this will NOT complete the call if the browser stops Javascript all together. It will, however, complete it as soon as the tab has been given focus again if enough time has passed in the interim. There is no way for a website to alter this sort of browser behavior from the scripting side.
Hope that helps!