I'm trying to get this code to change the page title based on array elements. But there is something wrong with this code. I need the page title show the entire array only when the browser tab is inactive. When the browser tab is active show the real page title. This is the code that I got so far
Here is a fiddle: https://jsfiddle.net/hgmvqasn/2/
/*
*
Title Change Plugin, adapted
*
*/
window.onload = function() {
var pageTitle = document.title;
var appeal = ["Hello! ♥","Welcome Back!", "Are you sure?"];
var blinkEvent = null;
document.addEventListener('visibilitychange', function(e){
var isPageActive = document.visibilityState;
console.log(isPageActive);
if (isPageActive == "hidden") {
blinkEvent;
} else {
document.title = pageTitle;
clearInterval(blinkEvent);
}
})
blinkEvent = setInterval(function() {
function blink(){
for (i = 0; i < appeal.length; i++){
document.title = appeal[i];
console.log(appeal[i]);
}
// To make instant page title change (no wait the interval)
document.title = appeal[1];
}
}, 1900);
};
The code above does not display all items in the array or displays them in wrong way. In addition the interval is not interrupted when the tab becomes active again.Can someone help me?
You shouldn't have the for loop. You just want one timer, not a timer for each string in the appeal array. That timer should increment the index and display the next title.
window.onload = function() {
var pageTitle = document.title;
var appeal = ["Hello! ♥", "Welcome Back!", "Are you sure?"];
var appeal_index = 0;
var blinkEvent = null;
document.addEventListener('visibilitychange', function(e) {
var isPageActive = document.visibilityState;
console.log(isPageActive);
if (isPageActive == "hidden") {
start_timer();
} else {
document.title = pageTitle;
clearInterval(blinkEvent);
}
})
function blink() {
document.title = appeal[appeal_index];
console.log(appeal[appeal_index]);
appeal_index++;
if (appeal_index >= appeal.length) { // wrap around to beginning
appeal_index = 0;
}
}
function start_timer() {
blink();
blinkEvent = setInterval(blink, 1900);
}
};
I was wondering why my program crashes after its made its first match....any ideas would be greatly appreciated. Below is the code snippet. Thanks for the input!
var clicks = 0; //counts how may picks have been made in each turn
var firstchoice; //stores index of first card selected
var secondchoice; //stores index of second card selected
var match = 0; //counts matches made
var backcard = "deck.jpg"; //shows back of card when turned over
var faces = []; //array to store card images
faces[0] = 'pic1.jpg';
faces[1] = 'pic2.jpg';
faces[2] = 'pic3.jpg';
faces[3] = 'pic3.jpg';
faces[4] = 'pic2.jpg';
faces[5] = 'pic1.jpg';
function choose(card) {
if (clicks === 2) {
return;
}
if (clicks === 0) {
firstchoice = card;
document.images[card].src = faces[card];
clicks = 1;
} else {
clicks = 2;
secondchoice = card;
document.images[card].src = faces[card];
timer = setInterval("check()", 1000);
}
}
/* Check to see if a match is made */
function check() {
clearInterval(timer); //stop timer
if (faces[secondchoice] === faces[firstchoice]) {
match++;
document.getElementById("matches").innerHTML = match;
} else {
document.images[firstchoice].src = backcard;
document.images[secondchoice].src = backcard;
clicks = 0;
return;
}
}
The first parameter of setInterval needs to be a function not a string pretending to be a function. So you would want this:
timer = setInterval(function() { check(); }, 1000);
Of course, you can simplify:
timer = setInterval(check, 1000);
Not sure why you're using setInterval() here. You could more easily just do:
timer = setTimeout(check, 1000);
The advantage is there is no interval to clear in the check() function.
The other issue is that you are not resetting your 'clicks' counter to 0 when there is a match.
You want this:
function check() {
clearInterval(timer); //stop timer
if (faces[secondchoice] === faces[firstchoice]) {
match++;
document.getElementById("matches").innerHTML = match;
} else {
document.images[firstchoice].src = backcard;
document.images[secondchoice].src = backcard;
}
clicks = 0;
}
I think you have to declare you timer function globally. Its only defined in the scope of the first function, so in the second when you try to clear it nothing happens:
var timer = ''; //Declare timer up here first!
function choose(card) { ... }
function check() { ... }
I am using google maps and i am trying to put a pause in execution to prevent QUERY_LIMIT usage issue. My function that plots the addresses looks like this.
The code works, however i want to try setTimeout or setInterval to see if its going to look better on UI.
How do i call it, what should be the first argument?
Thanx alot.
vLocations = [];
for (var i = 0; i < vAddresses.length; i++) {
//pause to prevent OVER_QUERY_LIMIT issue
//geocode "free" usage limit is 5 requests per second
//setTimeout(PlotAddressesAsUnAssigned, 1000);
//sleep(500);
//this will resolve the address and store it in vLocations
AddWaypointAndUnassigned(vAddresses[i]);
var z = i % 4;
if (z==0 && i != 0) {
//sleep after every 5th geocode call
//alert('going to sleep...i: ' + i);
//sleep(3000);
}
}
Doing a pause (asynchronous execution) inside a loop (synchronous) will usually result in a lot of trouble.
You can use recursive calls that are done only when a timeout ends.
var vLocations = [];
// Manages the timeout and recursive calls
function AddWaypointAndUnassignedWithPause(index){
setTimeout(function(){
// When the timeout expires, we process the data, and start the next timeout
AddWaypointAndUnassigned(vAddresses[index]);
// Some other code you want to execute
var z = i % 4;
if (z==0 && i != 0) {
//sleep after every 5th geocode call
//alert('going to sleep...i: ' + i);
//sleep(3000);
}
if(index < vAddresses.length-1)
AddWaypointAndUnassignedWithPause(++index);
}, 1000);
}
// Start the loop
AddWaypointAndUnassignedWithPause(0);
JSFiddle example.
Try this, hope this will help
vLocations = [];
for (var i = 0; i < vAddresses.length; i++) {
//pause to prevent OVER_QUERY_LIMIT issue
setTimeout(function(){
//this will resolve the address and store it in vLocations
AddWaypointAndUnassigned(vAddresses[i]);
}, 500);
var z = i % 4;
if (z==0 && i != 0) {
//sleep after every 5th geocode call
//alert('going to sleep...i: ' + i);
//sleep(3000);
}
}
What about a waiting line, thats fired when an item is added and stopped when there are no items left.
With setTimeout:
var INTERVAL = 1000 / 5;
var to = null;
var vLocations = [];
function addAddress(vAddress) {
vLocations.push(vAddress);
startTimeout();
}
function startTimeout() {
if( to === null ) {
to = setTimout(processLocation, INTERVAL);
}
}
function processLocation() {
if( vLocations.length ) {
var vAddress = vLocations.shift();
AddWaypointAndUnassigned(vAddress);
to = setTimout(processLocation, INTERVAL);
} else {
to = null;
}
}
With setInterval:
var INTERVAL = 1000 / 5;
var to = null;
var vLocations = [];
function addAddress(vAddress) {
vLocations.push(vAddress);
startInterval();
}
function startInterval() {
if( to === null ) {
to = setInterval(processLocation, INTERVAL);
}
}
function processLocation(cb) {
if( vLocations.length ) {
var vAddress = vLocations.shift();
AddWaypointAndUnassigned(vAddress);
} else
clearInterval(to);
to = null;
}
}
I have a progress bar that I update in a loop of many iterations.
https://jsfiddle.net/k29qy0do/32/
(open the console before you click the start button)
var progressbar = {};
$(function () {
progressbar = {
/** initial progress */
progress: 0,
/** maximum width of progressbar */
progress_max: 0,
/** The inner element of the progressbar (filled box). */
$progress_bar: $('#progressbar'),
/** Set the progressbar */
set: function (num) {
if (this.progress_max && num) {
this.progress = num / this.progress_max * 100;
console.log('percent: ' + this.progress + '% - ' + num + '/' + this.progress_max);
this.$progress_bar.width(String(this.progress) + '%');
}
},
fn_wrap: function (num) {
setTimeout(function() {
this.set(num);
}, 0);
}
};
});
$('#start_button').on('click', function () {
var iterations = 1000000000;
progressbar.progress_max = iterations;
var loop = function () {
for (var i = 1; i <= iterations; i++) {
if (iterations % i === 100) {
progressbar.set(i); //only updates the progressbar in the last iteration
//progressbar.fn_wrap(i); //even worse, since no output to the console is produced
}
}
}
//setTimeout(loop, 0);
loop();
});
The console is updated iteratively as expected.
However, the progressbar is not updating.
The problem is that the browser window seems to 'hang' until the loop finishes.
Only the console is updated, not the progressbar.
I have tried to add the setTimeout, as suggested below, in several places.
But that just makes things worse, because I then do not even get the console to output the progress while executing the loop.
Okay, I found a solution in the answer to this question:
Javascript: How to update a progress bar in a 'for' loop
var i = 0;
(function loop() {
i++;
if (iterations % i === 100) {
progressbar.set(i); //updates the progressbar, even in loop
}
if (i < iterations) {
setTimeout(loop, 0);
}
})();
My solution:
https://jsfiddle.net/ccvs4rer/3/
Lets break this down to steps
Step 1: Clean up HTML
Assuming the purpose of your question is to understand how to work the progress bar and not the styles or the labels (loading, please be patient, etc.). Lets just have the progress bar and the start button.
<div id='progressbar-outer' style="">
<div id='progressbar' style=""></div>
</div>
<button id="start_button">Start</button>
Step 2: The Styles
Lets make the progress bar visible to the user
#progressbar-outer {
height:2em;
border:5px solid #000;
width:15em;
}
#progressbar {
width:0%;
background-color:#F00;
height:100%;
}
Step 3: Using setTimeout where it belongs
In your code, you have used setTimeout to set the value of your progress bar. However, the for loop is still active.
for (var i = 1; i <= iterations; i++) {
if (iterations % i === 100) {
progressbar.set(i); //only updates the progressbar in the last iteration
//progressbar.fn_wrap(i); //even worse, since no output to the console is produced
//setTimeout(function() {
// progressbar.set(i);
//}, 0);
}
}
The use of setTimeout does not affect the rest of the code. Hence, the UI was held hostage till the loop ended. Try the following code.
$('#start_button').on('click', function () {
var iterations = 100;
progressbar.progress_max = iterations;
var loop = function (value) {
progressbar.set(value);
if (value < iterations) setTimeout(function () {
loop(value + 1)
}, 30);
else $('#progressbar').css('background-color', '#0F0');
}
loop(1);
});
Preview
Try this fiddle: https://jsfiddle.net/Ljc3b6rn/4/
What you really want is an Asynchronous loop to allow the browser to update the DOM in between iterations.
JSFiddle: http://jsfiddle.net/u5b6gr1w/
function delayedLoop(collection, delay, callback, context) {
context = context || null;
var i = 0,
nextInteration = function() {
if (i === collection.length) {
return;
}
callback.call(context, collection[i], i);
i++;
setTimeout(nextInteration, delay);
};
nextInteration();
}
Some HTML:
<div class="progress-bar"><div style="width: 0"></div></div>
A splash of CSS:
.progress-bar {
border: 1px solid black;
background-color: #f0f0f0;
}
.progress-bar div {
background-color: red;
height: 1.25em;
}
And some JavaScript to wire things together:
var progressBar = document.querySelector(".progress-bar div"),
items = [1,2,3,4,5,6,7,8,9,10];
delayedLoop(items, 500, function(item, index) {
var width = (item / items.length * 100) + "%";
progressBar.style.width = width;
progressBar.innerHTML = width;
});
My guess would be that all your progress updates are running in the same call stack. While JavaScript code is running, the DOM cannot update. Maybe this question will help you come up with a work-around.
What do you wnat to do? Why do you need it? You should only use a progressbar when you have to wait for something to finish. But we don't know what you do on your page.
If you want to display the progress of an ajax upload:
$.ajax({
...
xhr: function() {
var xhr = $.ajaxSettings.xhr();
$(xhr.upload).bind("progress", function(event) {
var e = event.originalEvent;
var percent = 0;
if (e.lengthComputable)
percent = Math.ceil(e.loaded/e.total*100);
$("#progress").width(percent+"%");
});
return xhr;
}
...
});
For images, you need an ajax call:
$.ajax({
method: "GET",
url: "http://example.com/path/image.jpg",
xhr: function() {/* see the code above*/ }
...
});
For getting the content of an uploaded file:
var reader = new FileReader();
reader.readAsText(uploadedFile);
$(reader).bind("progress", function(e) {
var percent = 0;
if (e.lengthComputable)
percent = Math.ceil(e.loaded/e.total*100);
$("#progress").css("width", percent+"%");
});
For large around of process, like math or appending a lot of divs that will take 10+ secons:
Main.js:
var worker = new Worker("Worker.js");
$(worker).bind("message", function(data) {
$("#progress").width((data*100)+"%");
});
Worker.js:
var total = 43483,
finished = 0,
doStuff = function() {
++finished;
return 1+1;
};
setInterval(function()
{
self.postMessage(finished/total);
}, 100);
for (var i = 0; i < total; ++i)
setTimeout(doStuff, i*10);
Because it's nice, and you want to tell the user there's a progress when there isn't, just animate the div:
$("#progress").animate({width: "100%"}, 3000);
You can use promises to wait until the width is set before continuing the loop.
Updating the progress bar for 1000000000 iterations will be slow if you go 1 by 1, so you might find it useful to decrease the update frequency.
Instead of a for loop, I used a recursive function that loops when the promise has been fulfilled.
set: function (num) {
var deferred = $.Deferred();
if (this.progress_max && num) {
this.progress = num / this.progress_max * 100;
var self = this;
self.$progress_bar.animate({"width": String(this.progress) + '%'}, "fast", function() {
deferred.resolve();
});
return deferred;
}
}
$('#start_button').on('click', function () {
var iterations = 1000000000;
var i = 0;
progressbar.progress_max = iterations;
var loop = function(){
i+=100000000;
if(i <= iterations){
progressbar.set(i).then(function(){
loop();
}); ;
}
};
loop();
});
https://jsfiddle.net/k29qy0do/34/
You have to use window.requestAnimationFrame, otherwise the browser will block until your loop is finished. The callback passed to requestAnimationFrame will get a timestamp as a parameter which you might be able to use for calculations of the progress.
This are my 2 takes on the question:
Using a web worker. The webworker blob code comes from here
Web worker code:
<script type="text/ww">
function loop(e) {
var data = JSON.parse(e.data);
var i = parseInt(data.i, 10);
var iterations = parseInt(data.iterations, 10);
while (iterations % ++i !== 100 && i <= iterations);
if(i <= iterations) {
self.postMessage(JSON.stringify({ i: i, iterations: iterations }));
}
}
self.onmessage = function(e) {
loop(e);
};
</script>
The code:
var ww = document.querySelector('script[type="text/ww"]'),
code = ww.textContent,
blob = new Blob([code], {type: 'text/javascript'}),
blobUrl = URL.createObjectURL(blob),
worker = new Worker(blobUrl);
worker.onmessage = function(e) {
var data = JSON.parse(e.data);
var i = parseInt(data.i, 10);
var iterations = parseInt(data.iterations, 10);
progressbar.set(i);
worker.postMessage(JSON.stringify({ i: i, iterations: iterations }));
}
$('#start_button').on('click', function () {
var iterations = 1000000000;
progressbar.progress_max = iterations;
worker.postMessage(JSON.stringify({ i: 0, iterations: iterations }));
});
The other idea hangs the UI thread, but changes the width visually, as I use requestAnimationFrame to break the counting, change width of the progressbar, and then continue the count.
function loopFrame(i, iterations) {
requestAnimationFrame(function() {
if (iterations % i === 100) {
progressbar.set(i);
}
if(i < iterations) {
loopFrame(i + 1, iterations);
}
});
}
$('#start_button').on('click', function () {
var iterations = 1000000000;
console.log(iterations);
progressbar.progress_max = iterations;
loopFrame(0, iterations);
});
Maybe this will be usefull.
var service = new Object();
//function with interrupt for show progress of operations
service.progressWhile = new Object();
service.progressWhile.dTime = 50; //step ms between callback display function
service.progressWhile.i = 0; //index
service.progressWhile.timer = 0; //start time for cycle
//#parametr arr - array for actions
//#parametr actionCallback - The function for processing array's elements
//#parametr progressCallback - function to display the array index
function progressWhile(arr, actionCallback, progressCallback) {
try {
var d = new Date();
service.progressWhile.timer = d.getTime();
log(service.progressWhile.i);
if (service.progressWhile.i >= arr.length) {
service.progressWhile.i = 0;
return;
}
while (service.progressWhile.i < arr.length) {
actionCallback(arr[service.progressWhile.i++]);
d = new Date();
if (d.getTime() - service.progressWhile.timer > service.progressWhile.dTime) {
break;
}
}
if (progressCallback != undefined)
progressCallback(service.progressWhile.i);
} catch (er) {
log(er);
return;
}
setTimeout(function () {
progressWhile(arr, actionCallback, progressCallback);
}, 0);
}
Here's updated fiddle
I used animate to make it a progress bar like look and feel.
Hope this will help you.
var progressbar = {};
$(function() {
progressbar = {
/** initial progress */
progress : 0,
/** maximum width of progressbar */
progress_max : 0,
/** The inner element of the progressbar (filled box). */
$progress_bar : $('#progressbar'),
/** Method to set the progressbar.*/
set : function(num) {
if (this.progress_max && num) {
this.progress = num / this.progress_max * 100;
console.log('percent: ' + this.progress + '% - ' + num + '/' + this.progress_max);
$('#progressbar').animate({
width : String(this.progress) + '%',
}, 500, function() {
// Animation complete.
});
}
},
fn_wrap : function(num) {
setTimeout(function() {
this.set(num);
}, 0);
}
};
});
$('#start_button').on('click', function() {
$('#progressbar').css('width', '0%');
var iterations = 1000000000;
progressbar.progress_max = iterations;
var loop = function() {
for (var i = 1; i <= iterations; i++) {
if (iterations % i === 100) {
progressbar.set(i);
//only updates the progressbar in the last iteration
}
}
}
loop();
});
Fiddler
[1]: https://jsfiddle.net/k29qy0do/21/
How would I have the h1 change for each iteration of the loop? This code now only displays the h1 text after everything is done.
for (i=0; i<array.length; i++) {
$("body > h1").text("Processing #" + i);
// things that take a while to do
}
Additional info: if I resize the window as it loops, the html updates.
var array = ['one', 'two', 'three']
var i = 0;
var refreshIntervalId = setInterval(function() {
length = array.length;
if (i < (array.length +1)) {
$("h1").text("Processing #" + i);
} else {
clearInterval(refreshIntervalId);
}
i++
}, 1000);
http://jsfiddle.net/3fj9E/
Use a setInterval with a one-millisecond delay:
var i=0, j=array.length;
var iv = setInterval(function() {
$("h1").text("Processing #" + i);
// things that take a while to do
if (++i>=j) clearInterval(iv);
}, 1);
http://jsfiddle.net/mblase75/sP9p7/
Sometimes you can force a render by forcing a recalculation of layout
for (i=0; i<array.length; i++) {
$("body > h1").text("Processing #" + i)
.width(); // force browser to recalculate layout
// things that take a while to do
}
It might not work in all browsers.
A better way, that does not block the browser so much:
function doThings(array) {
var queueWork,
i = -1,
work = function () {
// do work for array[i]
// ...
queueWork();
};
queueWork = function () {
if (++i < array.length) {
$("body > h1").text("Processing #" + i);
setTimeout(work, 0); // yield to browser
}
};
}
doThings(yourArray);
DEMO
I've spent a bit of time working out a jquery function that seems to solve this. Basically, it's a process handler that you can add any number of processes to and then call run to sequentially call these in a asynchronous way.
$.fn.LongProcess = function () {
var _this = this;
this.notifications = [];
this.actions = [];
this.add = function (_notification, _action) {
this.notifications.push(_notification);
this.actions.push(_action);
};
this.run = function () {
if (!_this.actions && !_this.notifications) {
return "Empty";
}
//******************************************************************
//This section makes the actions lag one step behind the notifications.
var notification = null;
if (_this.notifications.length > 0) notification = _this.notifications.shift();
var action = null;
if ((_this.actions.length >= _this.notifications.length + 2) || (_this.actions.length > 0 && _this.notifications.length == 0))
action = _this.actions.shift();
//****************************************************************
if (!action && !notification) {
return "Completed";
}
if (action) action();
if (notification) notification();
setTimeout(_this.run, 1000);
//setTimeout(_this.run,1); //set to 1 after you've entered your actual long running process. The 1000 is there to just show the delay.
}
return this;
};
How to use with <h1 class="processStatus"></h1>:
$(function () {
var process = $().LongProcess();
//process.add(notification function, action function);
process.add(function () {
$(".processStatus").text("process1");
}, function () {
//..long process stuff
alert("long process 1");
});
process.add(function () {
$(".processStatus").text("process2");
}, function () {
//..long process stuff
alert("long process 2");
});
process.add(function () {
$(".processStatus").text("process3");
}, function () {
//..long process stuff
alert("long process 3");
});
process.run();
});
if the process is very long you can use this script which shows every notification for a specific time interval.
here is the code..
html
<div id="ccNotificationBox"></div>
css
#ccNotificationBox{
-webkit-animation-name:;
-webkit-animation-duration:2s;/*Notification duration*/
box-sizing:border-box;
border-radius:16px;
padding:16px;
background-color:rgba(0,0,0,0.7);
top:-100%;
right:16px;
position:fixed;
color:#fff;
}
#ccNotificationBox.active{
-webkit-animation-name:note;
top:16px;
}
#-webkit-keyframes note{
0% {opacity:0;}
20% {opacity:1;}
80% {opacity:1;}
100% {opacity:0;}
}
javascript
var coccoNotification=(function(){
var
nA=[],
nB,
rdy=true;
function nP(a){
nA.push(a);
!rdy||(nR(),rdy=false);
}
function nR(){
nB.innerHTML=nA[0];console.log(nA[0]);
nB.offsetWidth=nB.offsetWidth;//reflow ios
nB.classList.add('active');
}
function nC(){
nB.classList.remove('active');
nB.innerHTML='';
nA.shift();
nA.length>0?nR():(rdy=true);
}
function init(){
nB=document.getElementById('ccNotificationBox');
nB.addEventListener('webkitAnimationEnd',nC,false);
window.removeEventListener('load',init,false);
}
window.addEventListener('load',init,false);
return nP
})();
usage
coccoNotification('notification 1');
example
http://jsfiddle.net/f6dkE/1/
info
the example above is perfect for external js as you use just one global variable which is the name of the function ... in my case coccoNotification
here is a different approach but it does the same
http://jsfiddle.net/ZXL4q/11/