Develop Reference

Javascript number counter with cache

I have this script for to increment a counter by one after 1 second , but when I refresh the page I need to remember the last number I counted.
Example: Currently, I have 40. When I refresh the page I need to start counting after 40 not reset to 1. Is this possible?
function animateValue(id) {
var obj = document.getElementById(id);
var current = parseInt(obj.innerHTML);
setInterval(function() {
current++;
// Update the contents of the element
obj.innerHTML = current;
}, 1000);
}
animateValue('value');
<h1>
<div id="value">1</div>
</h1>

You can store the counter progress in localStorage, then retrieve the value on page load and start counting from there:
var obj = document.getElementById("value");
let counterStorage = localStorage.getItem('counter')
if(counterStorage) obj.innerHTML = counterStorage
function animateValue(id) {
var current = parseInt(obj.innerHTML);
setInterval(function() {
current++;
localStorage.setItem('counter', current)
obj.innerHTML = current;
}, 1000);
}
animateValue('value');

Use localstorage. If not exists then set and if exists use the value from localstorage.
function animateValue(id){
const obj = document.getElementById(id);
let current = parseInt(obj.innerHTML);
const storageTime = localStorage.getItem("mytime")
if ( storageTime === null) {
localStorage.setItem("mytime", current);
} else {
current = storageTime;
}
setInterval(function(){
current++;
localStorage.setItem("mytime", current);
// Update the contents of the element
obj.innerHTML = current;
},1000);
}
animateValue('value');
<h1><div id="value">1</div></h1>

you can use window.localstorage. the code will look something like this
window.localstorage.setItem('timer', timer)

Play Boostrap Popover on loop

DEMO: http://jsfiddle.net/0s730kxx/
I'm trying to open Bootstrap Popover to auto-open on loop but so far I've have manage only to auto-play once.
HTML:
<div class="container">
Hover Left |
Hover Right |
Click Me
</div>
JS:
$(document).ready(function(){
var time = 1000;
var len = $('.myclass').length;
var count = 0;
var fun = setInterval(function(){
count++;
if(count>len){
clearInterval(fun);
}
$('.p'+count).popover('show');
if(count>1){
var pre = count-1;
$('.p'+pre).popover('hide');
}
}, time);
});
Could anyone help? I want it on loop so it plays forever or atleast 10 or 20 times.

Modify javascript part of your fiddle like this:
$(document).ready(function(){
var time = 1000;
var len = $('.myclass').length;
var count = 0;
var fun = setInterval(function(){
count++;
if(count>len){
$('.p'+(count-1)).popover('hide');
count = 1;
//clearInterval(fun);
}
$('.p'+count).popover('show');
if(count>1){
var pre = count-1;
$('.p'+pre).popover('hide');
}
}, time);
});
Since you are not clearing the interval in this modified snippet, it will run forever as you expected.

Thats because you have added line
if(count>len){
clearInterval(fun);
}
After showing them 1 time count is 3 and clearInterval(fun) is called
which terminates further call to function fun().

Original comment: You can't clear the interval and expect the loop to continue! Instead of clearing set the count back to 0. But you'll also need to remember to hide the last popover.
var fun = setInterval(function(){
count++;
$('.p' + count).popover('show');
if(count > 1){
$('.p' + (count - 1)).popover('hide');
}
if(count > len){
count = 0;
}
}, time);
Here is a fiddle: http://jsfiddle.net/89gcqnfm/

Simplicity and modular arithmetic are your friends:
$(document).ready(function(){
var time = 1000;
var eles = $('.myclass');
var count = 0;
var fun = setInterval(function(){
if(eles.length < 1)
return (console.log("No elements found!")&&!1) || clearInterval(fun);
eles.eq(count%eles.length).popover('hide');
eles.eq(++count%eles.length).popover('show');
}, time);
});
https://jsfiddle.net/L2487dfy/

Image animation with speed control

We have some problem with our image animation with speed control.
It make use of a timeout to change the image, but we want to change the timeout value with a slider, but for some sort of reason, it doesn't work. Can someone help us out ?
We have a Jfiddle here: http://jsfiddle.net/Kbroeren/fmd4xbew/
Thanks! Kevin
var jArray = ["http://www.parijsalacarte.nl/images/mickey-mouse.jpg", "http://www.startpagina.nl/athene/dochters/cliparts-disney/images/donad%20duck-106.jpg", "http://images2.proud2bme.nl/hsfile_203909.jpg"];
var image_count = 0;
function rollover(image_id, millisecs) {
var image = document.getElementById(image_id);
image.src = jArray[image_count];
image_count++;
if (image_count >= jArray.length) {
image_count = 0;
}
var timeout = setTimeout("rollover('" + image_id + "'," + millisecs + ");", millisecs);
}
rollover("img1", 200);
$(function () {
var value;
var $document = $(document),
$inputRange = $('input[type="range"]');
// Example functionality to demonstrate a value feedback
function valueOutput(element) {
var value = element.value,
output = element.parentNode.getElementsByTagName('output')[0];
output.innerHTML = value;
}
for (var i = $inputRange.length - 1; i >= 0; i--) {
valueOutput($inputRange[i]);
};
$document.on('change', 'input[type="range"]', function (e) {
valueOutput(e.target);
rollover("img1", 200);
});
// end
$inputRange.rangeslider({
polyfill: false
});
});

You keep creating more and more infinite function calls without stopping them.
After you call your function the first time, it keeps calling itself.
then you call it again with different interval (millisecs) and it will also start call itself....
You can try two different approach.
1.Use setInterval instead of setTimeout. Use clearInterval to clear the interval before setting it with a new value.
/// Call animation() every 200 ms
var timer = setInterval("Animation()",200);
function ChageSpeed(miliseces){
///Stop calling Animation()
clearInterval(timer);
/// Start calling Animation() every "miliseces" ms
timer = setInterval("Animation()",miliseces);
}
function Animation(){
/// Animation code goes here
}
2.Or, Instead, Set your interval as a global variable (not cool) and just change it value when the user want to change the animation speed.
var millisecs = 200;
function rollover(image_id) {
var image = document.getElementById(image_id);
image.src = jArray[image_count];
image_count++;
if (image_count >= jArray.length) {
image_count = 0;
}
var timeout = setTimeout("rollover('" + image_id + "'," + millisecs + ");", millisecs);
}
$document.on('change', 'input[type="range"]', function (e) {
valueOutput(e.target);
millisecs = YourNewValue;
});

Resetting jquery varible to lowest possible value that doesn't exist

This script generate divs with cloud images that fly from left to right with random height and intervals. It generally works but it keeps incrementing divs "id" infinitely. I can't figure out how to reset the counter being safe that never two identical "id"s will exist in the same time.
function cloudgenerator(){
var nr=1;
var t1 = 20000;
var t2 = 50000;
function cloud(type,time,nr){
$("#sky").append("<div id=\"cloudFL"+nr+"\" class=\"cloud"+type+"\" ></div>");
setTimeout(function() {
$("#cloudFL"+nr).css({top:Math.floor(Math.random() * 400)+'px'}).animate({
left:'100%',
},time,'linear',function(){$(this).remove();
});
}, Math.floor(Math.random() * t1));
};
function wave(){
var tx = 0;
setInterval(function(){
cloud(1,t1,nr);
nr++;
var n = $( "div.cloud1" ).length;
$( "span" ).text( "There are " + n +" n and "+ tx +" tx")
if(tx < n){tx = n}
else(tx = 1)
},500);
};
wave()};
cloudgenerator()
In the bottom, there is an instruction that checks if number of divs is starting to drop and presents those values in span for debugging.

Quick and easy solutionYou could loop through the id's in JQuery, starting from the lowest number, until you find a JQuery selector that yields 0 results...
var newid = 0;
var i = 1;
while(newid == 0) {
if( $('#cloudFL' + i).length == 0 ) { newid = i; }
else { i++; }
}
JSFIDDLE DEMO
Alternative solution (scalable)
Given that you may have many clouds onscreen at one time, you could try this alternative approach.
This approach creates an array of 'used ids' and the wave function then checks if any 'used ids' are available before creating a new id for the cloud function. This will run quite a bit more efficiently that then above 'quick fix solution' in situations where many clouds appear on screen.
function cloudgenerator(){
var nr=1;
var t1 = 20000;
var t2 = 50000;
var spentids = [];
function cloud(type,time,id){
$("body").append('<div id="' + id + '" class="cloud' + type + '" >' + id + '</div>');
setTimeout(function() {
$('#'+id).css({top:Math.floor(Math.random() * 400)+'px'}).animate({
left:'100%',
},time,'linear',function(){
spentids.push( $(this).attr('id') );
$(this).remove();
});
}, Math.floor(Math.random() * t1));
};
function wave(){
setInterval(function(){
if(spentids.length == 0) {
cloud(1,t1,"cloudFL" + nr);
nr++;
} else {
spentids = spentids.sort();
cloud(1,t1,spentids.shift());
}
},500);
};
wave()};
cloudgenerator()
JSFIDDLE DEMO - ALTERNATIVE

Why not get the timestamp and add this to your id?
If you don´t need the ids i would stick to #hon2a and just add the styling to the class and remove the ids.
And another solution:
You could make a check if ID xyz is used. Like this e.g.
var cloudCount = jQuery('.cloud20000').length + jQuery('.cloud50000').length + 10;
for(var i = 0; i <= cloudCount; i++) {
if(jQuery('#cloudFL' + i).length <= 0) {
nr = i;
return false;
}
}
cloud(1,t1,nr);

Countdown timer for use in several places at same page

I want to make a countdown timer, that can be used on several places in the same page - so I think it should be a function in some way.
I really want it to be made with jQuery, but I cant quite make it happen with my code. I have e.g. 10 products in a page, that I need to make a countdown timer - when the timer is at 0 I need it to hide the product.
My code is:
$(document).ready(function(){
$(".product").each(function(){
$(function(){
var t1 = new Date()
var t2 = new Date()
var dif = t1.getTime() - t2.getTime()
var Seconds_from_T1_to_T2 = dif / 1000;
var Seconds_Between_Dates = Math.abs(Seconds_from_T1_to_T2);
var count = Seconds_Between_dates;
var elm = $(this).attr('id');
alert(elm);
countdown = setInterval(function(){
$(elm + " .time_left").html(count + " seconds remaining!");
if (count == 0) {
$(this).css('display','none');
}
count--;
}, 1000);
});
});
});
EDIT 1:
$(document).ready(function(){
$(".product").each(function(){
var elm = $(this).attr('id');
$(function(){
var t1 = new Date()
var t2 = new Date()
var dif = t1.getTime() - t2.getTime()
var Seconds_from_T1_to_T2 = dif / 1000;
var Seconds_Between_Dates = Math.abs(Seconds_from_T1_to_T2);
var count = Seconds_Between_dates;
alert(elm);
countdown = setInterval(function(){
$(elm + " .time_left").html(count + " seconds remaining!");
if (count == 0) {
$(this).css('display','none');
}
count--;
}, 1000);
});
});
});
Do you have any solutions to this?

I'd probably use a single interval function that checks all the products. Something like this:
$(function() {
/* set when a product should expire.
hardcoded to 5 seconds from now for demonstration
but this could be different for each product. */
$('.product').each(function() {
$(this).data('expires', (new Date()).getTime() + 5000);
});
var countdown_id = setInterval(function() {
var now = (new Date()).getTime();
$('.product').each(function() {
var expires = $(this).data('expires');
if (expires) {
var seconds_remaining = Math.round((expires-now)/1000);
if (seconds_remaining > 0) {
$('.time-left', this).text(seconds_remaining);
}
else {
$(this).hide();
}
}
});
}, 1000);
});
You could also cancel the interval function when there is nothing left to expire.

Your problem seems to be that this doesn't refer to the current DOM element (from the each), but to window - from setTimeout.
Apart from that, you have an unnecessary domReady wrapper, forgot the # on your id selector, should use cached references and never rely on the timing of setInterval, which can be quite drifting. Use this:
$(document).ready(function(){
$(".product").each(function(){
var end = new Date(/* from something */),
toUpdate = $(".time_left", this);
prod = $(this);
countDown();
function countdown() {
var cur = new Date(),
left = end - cur;
if (left <= 0) {
prod.remove(); // or .hide() or whatever
return;
}
var sec = Math.ceil(left / 1000);
toUpdate.text(sec + " seconds remaining!"); // don't use .html()
setTimeout(countdown, left % 1000);
}
});
});