I use final countdown to countdown timer. I provide an enddate and it works fine.
<div class="js-countdown" data-enddate="2019/1/21 15:54"></div>
my js:
var $clock = $('.js-countdown');
var d = new Date(Date.parse($clock.data("enddate").replace(/ /g, "T")));
$clock.countdown(d, function(event) {
$(this).text(
event.strftime('%D days %H:%M:%S')
);
});
</script>
It really depends on user clock, for example, when user changes time or if clock is not synced, the countdown timer doesn't work as expected.
Server time: 13:54
User time: 13:54
End date: 15:54, then countdown shows: 2(hrs):00(mins). But if:
Server time: 13:54
User time: 14:54 (it changed deliberately)
End date: 15:54, then countdown shows 1(hrs):00(mins) as I want it be 2(hrs):00(mins). How can I do change this behavior? My goal is to achieve an independent countdown timer. Would you please give me hints about that?
Edit
Here, the timer updates date. Is it reasonable to send request every time that update event fire?
I'm not sure if this is the best approach, but by now, it works fine.
var now;
var it = 1;
now = new Date(Date.parse('#DateTime.UtcNow.ToString("u")'.replace(/ /g, "T")));
setInterval(setAndSyncTime, 1000);
function setAndSyncTime() {
var t1 = new Date();
var t2 = now;
var t3 = Math.abs(t1 - t2);
if (t3 > 2000) {
if (it === 10) {
it = 0;
$.ajax({
url: '/SyncTime',
type: 'get',
success: function (response) {
now = new Date(Date.parse(response.replace(/ /g, "T")));
}
});
} else {
now = now.setSeconds(now.getSeconds() + 1);
now = new Date(now);
}
} else {
now = now.setSeconds(now.getSeconds() + 1);
now = new Date(now);
}
it++;
}
and
public virtual JsonResult SyncTime()
{
return Json(DateTime.UtcNow.ToString("u"), JsonRequestBehavior.AllowGet);
}
I wrote the following script to measure the respondent's reaction time for each question. My question is how can I retrieve the reaction time?
Qualtrics.SurveyEngine.addOnload(function(){
var starttime = new Date().getTime();
var that = this;
this.hideNextButton();
this.questionclick = function(event,element){
if (element.type == 'radio') {
var endtime = new Date().getTime();
var reactiontime = endtime - starttime;
document.getElementById("QR~"+this.questionID).value = document.getElementById("QR~"+this.questionID).value + "X" + reactiontime + ",";
}
that.clickNextButton();
}
});
You can save reaction time to an embedded data variable. Define reactiontime as an embedded data variable in the survey flow prior to the question block. Then:
Qualtrics.SurveyEngine.addOnReady(function(){
var starttime = new Date().getTime();
$('NextButton').hide();
this.questionclick = function(event,element){
if (element.type == 'radio') {
var endtime = new Date().getTime();
var reactiontime = endtime - starttime;
Qualtrics.SurveyEngine.setEmbeddedData('reactiontime', reactiontime);
$('NextButton').click();
}
}
});
How can I create a JavaScript page that will detect the user’s internet speed and show it on the page? Something like “your internet speed is ??/?? Kb/s”.
It's possible to some extent but won't be really accurate, the idea is load image with a known file size then in its onload event measure how much time passed until that event was triggered, and divide this time in the image file size.
Example can be found here: Calculate speed using javascript
Test case applying the fix suggested there:
//JUST AN EXAMPLE, PLEASE USE YOUR OWN PICTURE!
var imageAddr = "http://www.kenrockwell.com/contax/images/g2/examples/31120037-5mb.jpg";
var downloadSize = 4995374; //bytes
function ShowProgressMessage(msg) {
if (console) {
if (typeof msg == "string") {
console.log(msg);
} else {
for (var i = 0; i < msg.length; i++) {
console.log(msg[i]);
}
}
}
var oProgress = document.getElementById("progress");
if (oProgress) {
var actualHTML = (typeof msg == "string") ? msg : msg.join("<br />");
oProgress.innerHTML = actualHTML;
}
}
function InitiateSpeedDetection() {
ShowProgressMessage("Loading the image, please wait...");
window.setTimeout(MeasureConnectionSpeed, 1);
};
if (window.addEventListener) {
window.addEventListener('load', InitiateSpeedDetection, false);
} else if (window.attachEvent) {
window.attachEvent('onload', InitiateSpeedDetection);
}
function MeasureConnectionSpeed() {
var startTime, endTime;
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
showResults();
}
download.onerror = function (err, msg) {
ShowProgressMessage("Invalid image, or error downloading");
}
startTime = (new Date()).getTime();
var cacheBuster = "?nnn=" + startTime;
download.src = imageAddr + cacheBuster;
function showResults() {
var duration = (endTime - startTime) / 1000;
var bitsLoaded = downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
ShowProgressMessage([
"Your connection speed is:",
speedBps + " bps",
speedKbps + " kbps",
speedMbps + " Mbps"
]);
}
}
<h1 id="progress">JavaScript is turned off, or your browser is realllllly slow</h1>
Quick comparison with "real" speed test service showed small difference of 0.12 Mbps when using big picture.
To ensure the integrity of the test, you can run the code with Chrome dev tool throttling enabled and then see if the result matches the limitation. (credit goes to user284130 :))
Important things to keep in mind:
The image being used should be properly optimized and compressed. If it isn't, then default compression on connections by the web server might show speed bigger than it actually is. Another option is using uncompressible file format, e.g. jpg. (thanks Rauli Rajande for pointing this out and Fluxine for reminding me)
The cache buster mechanism described above might not work with some CDN servers, which can be configured to ignore query string parameters, hence better setting cache control headers on the image itself. (thanks orcaman for pointing this out))
The bigger the image size is, the better. Larger image will make the test more accurate, 5 mb is decent, but if you can use even a bigger one it would be better.
Well, this is 2017 so you now have Network Information API (albeit with a limited support across browsers as of now) to get some sort of estimate downlink speed information:
navigator.connection.downlink
This is effective bandwidth estimate in Mbits per sec. The browser makes this estimate from recently observed application layer throughput across recently active connections. Needless to say, the biggest advantage of this approach is that you need not download any content just for bandwidth/ speed calculation.
You can look at this and a couple of other related attributes here
Due to it's limited support and different implementations across browsers (as of Nov 2017), would strongly recommend read this in detail
I needed a quick way to determine if the user connection speed was fast enough to enable/disable some features in a site I’m working on, I made this little script that averages the time it takes to download a single (small) image a number of times, it's working pretty accurately in my tests, being able to clearly distinguish between 3G or Wi-Fi for example, maybe someone can make a more elegant version or even a jQuery plugin.
var arrTimes = [];
var i = 0; // start
var timesToTest = 5;
var tThreshold = 150; //ms
var testImage = "http://www.google.com/images/phd/px.gif"; // small image in your server
var dummyImage = new Image();
var isConnectedFast = false;
testLatency(function(avg){
isConnectedFast = (avg <= tThreshold);
/** output */
document.body.appendChild(
document.createTextNode("Time: " + (avg.toFixed(2)) + "ms - isConnectedFast? " + isConnectedFast)
);
});
/** test and average time took to download image from server, called recursively timesToTest times */
function testLatency(cb) {
var tStart = new Date().getTime();
if (i<timesToTest-1) {
dummyImage.src = testImage + '?t=' + tStart;
dummyImage.onload = function() {
var tEnd = new Date().getTime();
var tTimeTook = tEnd-tStart;
arrTimes[i] = tTimeTook;
testLatency(cb);
i++;
};
} else {
/** calculate average of array items then callback */
var sum = arrTimes.reduce(function(a, b) { return a + b; });
var avg = sum / arrTimes.length;
cb(avg);
}
}
As I outline in this other answer here on StackOverflow, you can do this by timing the download of files of various sizes (start small, ramp up if the connection seems to allow it), ensuring through cache headers and such that the file is really being read from the remote server and not being retrieved from cache. This doesn't necessarily require that you have a server of your own (the files could be coming from S3 or similar), but you will need somewhere to get the files from in order to test connection speed.
That said, point-in-time bandwidth tests are notoriously unreliable, being as they are impacted by other items being downloaded in other windows, the speed of your server, links en route, etc., etc. But you can get a rough idea using this sort of technique.
Even though this is old and answered, i´d like to share the solution i made out of it 2020 base on Shadow Wizard Says No More War´s solution
I just merged it into an object that comes with the flexibility to run at anytime and run a callbacks if the specified mbps is higher or lower the measurement result.
you can start the test anywhere after you included the testConnectionSpeed Object by running the
/**
* #param float mbps - Specify a limit of mbps.
* #param function more(float result) - Called if more mbps than specified limit.
* #param function less(float result) - Called if less mbps than specified limit.
*/
testConnectionSpeed.run(mbps, more, less)
for example:
var testConnectionSpeed = {
imageAddr : "https://upload.wikimedia.org/wikipedia/commons/a/a6/Brandenburger_Tor_abends.jpg", // this is just an example, you rather want an image hosted on your server
downloadSize : 2707459, // Must match the file above (from your server ideally)
run:function(mbps_max,cb_gt,cb_lt){
testConnectionSpeed.mbps_max = parseFloat(mbps_max) ? parseFloat(mbps_max) : 0;
testConnectionSpeed.cb_gt = cb_gt;
testConnectionSpeed.cb_lt = cb_lt;
testConnectionSpeed.InitiateSpeedDetection();
},
InitiateSpeedDetection: function() {
window.setTimeout(testConnectionSpeed.MeasureConnectionSpeed, 1);
},
result:function(){
var duration = (endTime - startTime) / 1000;
var bitsLoaded = testConnectionSpeed.downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
if(speedMbps >= (testConnectionSpeed.max_mbps ? testConnectionSpeed.max_mbps : 1) ){
testConnectionSpeed.cb_gt ? testConnectionSpeed.cb_gt(speedMbps) : false;
}else {
testConnectionSpeed.cb_lt ? testConnectionSpeed.cb_lt(speedMbps) : false;
}
},
MeasureConnectionSpeed:function() {
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
testConnectionSpeed.result();
}
startTime = (new Date()).getTime();
var cacheBuster = "?nnn=" + startTime;
download.src = testConnectionSpeed.imageAddr + cacheBuster;
}
}
// start test immediatly, you could also call this on any event or whenever you want
testConnectionSpeed.run(1.5, function(mbps){console.log(">= 1.5Mbps ("+mbps+"Mbps)")}, function(mbps){console.log("< 1.5Mbps("+mbps+"Mbps)")} )
I used this successfuly to load lowres media for slow internet connections. You have to play around a bit because on the one hand, the larger the image, the more reasonable the test, on the other hand the test will take way much longer for slow connection and in my case I especially did not want slow connection users to load lots of MBs.
The image trick is cool but in my tests it was loading before some ajax calls I wanted to be complete.
The proper solution in 2017 is to use a worker (http://caniuse.com/#feat=webworkers).
The worker will look like:
/**
* This function performs a synchronous request
* and returns an object contain informations about the download
* time and size
*/
function measure(filename) {
var xhr = new XMLHttpRequest();
var measure = {};
xhr.open("GET", filename + '?' + (new Date()).getTime(), false);
measure.start = (new Date()).getTime();
xhr.send(null);
measure.end = (new Date()).getTime();
measure.len = parseInt(xhr.getResponseHeader('Content-Length') || 0);
measure.delta = measure.end - measure.start;
return measure;
}
/**
* Requires that we pass a base url to the worker
* The worker will measure the download time needed to get
* a ~0KB and a 100KB.
* It will return a string that serializes this informations as
* pipe separated values
*/
onmessage = function(e) {
measure0 = measure(e.data.base_url + '/test/0.bz2');
measure100 = measure(e.data.base_url + '/test/100K.bz2');
postMessage(
measure0.delta + '|' +
measure0.len + '|' +
measure100.delta + '|' +
measure100.len
);
};
The js file that will invoke the Worker:
var base_url = PORTAL_URL + '/++plone++experimental.bwtools';
if (typeof(Worker) === 'undefined') {
return; // unsupported
}
w = new Worker(base_url + "/scripts/worker.js");
w.postMessage({
base_url: base_url
});
w.onmessage = function(event) {
if (event.data) {
set_cookie(event.data);
}
};
Code taken from a Plone package I wrote:
https://github.com/collective/experimental.bwtools/blob/master/src/experimental/bwtools/browser/static/scripts/
It's better to use images for testing the speed. But if you have to deal with zip files, the below code works.
var fileURL = "your/url/here/testfile.zip";
var request = new XMLHttpRequest();
var avoidCache = "?avoidcache=" + (new Date()).getTime();;
request.open('GET', fileURL + avoidCache, true);
request.responseType = "application/zip";
var startTime = (new Date()).getTime();
var endTime = startTime;
request.onreadystatechange = function () {
if (request.readyState == 2)
{
//ready state 2 is when the request is sent
startTime = (new Date().getTime());
}
if (request.readyState == 4)
{
endTime = (new Date()).getTime();
var downloadSize = request.responseText.length;
var time = (endTime - startTime) / 1000;
var sizeInBits = downloadSize * 8;
var speed = ((sizeInBits / time) / (1024 * 1024)).toFixed(2);
console.log(downloadSize, time, speed);
}
}
request.send();
This will not work very well with files < 10MB. You will have to run aggregated results on multiple download attempts.
thanks to Punit S answer, for detecting dynamic connection speed change, you can use the following code :
navigator.connection.onchange = function () {
//do what you need to do ,on speed change event
console.log('Connection Speed Changed');
}
Improving upon John Smith's answer, a nice and clean solution which returns a Promise and thus can be used with async/await. Returns a value in Mbps.
const imageAddr = 'https://upload.wikimedia.org/wikipedia/commons/a/a6/Brandenburger_Tor_abends.jpg';
const downloadSize = 2707459; // this must match with the image above
let startTime, endTime;
async function measureConnectionSpeed() {
startTime = (new Date()).getTime();
const cacheBuster = '?nnn=' + startTime;
const download = new Image();
download.src = imageAddr + cacheBuster;
// this returns when the image is finished downloading
await download.decode();
endTime = (new Date()).getTime();
const duration = (endTime - startTime) / 1000;
const bitsLoaded = downloadSize * 8;
const speedBps = (bitsLoaded / duration).toFixed(2);
const speedKbps = (speedBps / 1024).toFixed(2);
const speedMbps = (speedKbps / 1024).toFixed(2);
return Math.round(Number(speedMbps));
}
I needed something similar, so I wrote https://github.com/beradrian/jsbandwidth. This is a rewrite of https://code.google.com/p/jsbandwidth/.
The idea is to make two calls through Ajax, one to download and the other to upload through POST.
It should work with both jQuery.ajax or Angular $http.
//JUST AN EXAMPLE, PLEASE USE YOUR OWN PICTURE!
var imageAddr = "https://i.ibb.co/sPbbkkZ/pexels-lisa-1540258.jpg";
var downloadSize = 10500000; //bytes
function ShowProgressMessage(msg) {
if (console) {
if (typeof msg == "string") {
console.log(msg);
} else {
for (var i = 0; i < msg.length; i++) {
console.log(msg[i]);
}
}
}
var oProgress = document.getElementById("progress");
if (oProgress) {
var actualHTML = (typeof msg == "string") ? msg : msg.join("<br />");
oProgress.innerHTML = actualHTML;
}
}
function InitiateSpeedDetection() {
ShowProgressMessage("Loading the image, please wait...");
window.setTimeout(MeasureConnectionSpeed, 1);
};
if (window.addEventListener) {
window.addEventListener('load', InitiateSpeedDetection, false);
} else if (window.attachEvent) {
window.attachEvent('onload', InitiateSpeedDetection);
}
function MeasureConnectionSpeed() {
var startTime, endTime;
var download = new Image();
download.onload = function () {
endTime = (new Date()).getTime();
showResults();
}
download.onerror = function (err, msg) {
ShowProgressMessage("Invalid image, or error downloading");
}
startTime = (new Date()).getTime();
var cacheBuster = "?nnn=" + startTime;
download.src = imageAddr + cacheBuster;
function showResults() {
var duration = (endTime - startTime) / 1000;
var bitsLoaded = downloadSize * 8;
var speedBps = (bitsLoaded / duration).toFixed(2);
var speedKbps = (speedBps / 1024).toFixed(2);
var speedMbps = (speedKbps / 1024).toFixed(2);
ShowProgressMessage([
"Your connection speed is:",
speedBps + " bps",
speedKbps + " kbps",
speedMbps + " Mbps"
]);
}
}
<h1 id="progress">JavaScript is turned off, or your browser is realllllly slow</h1>
Mini snippet:
var speedtest = {};
function speedTest_start(name) { speedtest[name]= +new Date(); }
function speedTest_stop(name) { return +new Date() - speedtest[name] + (delete
speedtest[name]?0:0); }
use like:
speedTest_start("test1");
// ... some code
speedTest_stop("test1");
// returns the time duration in ms
Also more tests possible:
speedTest_start("whole");
// ... some code
speedTest_start("part");
// ... some code
speedTest_stop("part");
// returns the time duration in ms of "part"
// ... some code
speedTest_stop("whole");
// returns the time duration in ms of "whole"
I'm trying to get server time at start and update it, cause i've to cotnrol some elements with real time. The problem is that if my serverTime doesn't have T the time is NaN on firefox and IE, but if i replace the empty space with T on chrome and IE i've a wrong time.
I now the work-around of replacing white space with T sucks but im outta of time :)
Thanks everybody
At start:
$tmpTime = date("Y-m-d H:i:s");
Head:
<script>
var serverTime = '<?=$tmpTime?>';
serverTime = serverTime.replace(" ", "T");
</script>
Script:
setInterval(function () {
console.log(serverTime);
var tmpTime = new Date(serverTime);
console.log(tmpTime);
var t = tmpTime.getTime();
t = t + 1000;
tmpTime = new Date(t);
serverTime = t;
if (tmpTime.getMinutes() < 10) {
var minutes = "0" + tmpTime.getMinutes();
} else {
var minutes = tmpTime.getMinutes();
};
newTime = tmpTime.getHours() + ":" + minutes;
$('#liveTime').text(newTime);
if ($("#program li[time-id='" + newTime + "'][class='alert']").length !== 0) {
alert("Lo streaming da te programmato sta per iniziare!");
$("#program li[time-id='" + newTime + "'][class='alert']").removeClass("alert");
}
titleToShow();
}, 1000);
function titleToShow() {
$("#program li").each(function () {
var prevTime = $(this).prev("li").attr("time-id");
var thisTime = $(this).attr("time-id");
var nextTime = $(this).next("li").attr("time-id");
currentTime = Date.parse('01/01/2011 ' + newTime);
prevTime = Date.parse('01/01/2011 ' + prevTime);
nextTime = Date.parse('01/01/2011 ' + nextTime);
thisTimeNew = Date.parse('01/01/2011 ' + thisTime);
if (currentTime >= thisTimeNew && currentTime < nextTime && currentTime > prevTime) {
title = $(this).find("p").text();
if (title != $("p#playingTitle").text()) {
$("p#playingTitle").text(title);
}
}
})
}
Don’t use a formated date, just pass the Unix timestamp value to the script (don’t forget to multiply it by 1000, because JS works with milliseconds).
var serverTime = <?php echo time(); ?>;
var tmpTime = new Date(serverTime * 1000);
Need that, the counter should be start after button click, when start count up - start button must be inactive, after count up finish - button must be active and have someone function.
var refDate = new Date("2013 01 18 16:41");
var prepend = "This is a message ";
var append = new Date(refDate).toLocaleString();
var refValue = "1,100.00";
function insertCommas(nAmt) {
var currAmt = nAmt.toFixed(2);
while (/(\d+)(\d{3})/.test(currAmt)) {
currAmt = currAmt.replace(/(\d+)(\d{3})/, "$1,$2");
}
return currAmt;
}
function dispCounter() {
var currDate = new Date();
var elapsedSeconds = Math.round((refDate - currDate) / 100);
var elapsedValue = elapsedSeconds / 100;
var nRef = refValue.replace(/\,/g, "");
var result = insertCommas(nRef - elapsedValue);
document.getElementById('upCount').innerHTML = prepend + " $" + result + " since " + append;
setTimeout("dispCounter()", 1500);
}
navigator.appName == "Microsoft Internet Explorer" ? attachEvent('onload', dispCounter, false) : addEventListener('load', dispCounter, false);