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Okay guys, I got a page, displaying 24/7, I got sunrise/sunset time that I'm getting from server (websockets, there is much more data, lets stick to this) and I got images of sun/moon.
What is the best way to change image on page, depending on daytime?
The point is: when image updating function should be called? Each day I should get new values, but I can't predict the time when I'll get those. If I will use delayed timers, how should I get timers updated, when I will recieve new sunrise/sunset time?
Take a look at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Timers. You can set a relative timeout by first determining what time it is, and using the offset to sunrise/sunset.
I think you can create a timer on your page which check the time of day every period of time (10 minutes) and compare it with the dates you got from server.
$(document).ready(function(){
setInterval(check_dates,60000);
});
function check_dates()
{
var now = new Date();
if(now>=sunrise_datetime && now< sunset_datetime)
{
$('body').html('<img src='sunrise_image.jpg' />');
}
else
{
$('body').html('<img src='sunset_image.jpg' />');
}
}
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I have some socket.io emits that I'd like to provide handling for when they are taking too long to get back from the server with their promise. But I also don't want to outright time them out. I have seen this on some websites where a loading spinner will add 'This seems to be taking longer than usual' text after 10 or so seconds.
How can I add a timeout-style method to a Javascript function that will do something after a certain amount of time, but will NOT cancel the original method?
Unless you have a global scope, you'll need to pass in two handlers
Something like this (I've generalised the flow because you've not provided enough information about your existing set up, so I hope it makes sense)
function doSocketRequest(normalHandler, tooLongHandler) {
let timer = null;
// set timeout to 5 seconds, if we hit it then trigger "tooLongHandler"
timer = setTimeout(tooLongHandler, 5000);
// When we receive our socket response for the event, clear the time and trigger "normalHandler"
socket.on('some_event_response', (response) => {
clearTimeout(timer);
normalHandler(response)
});
// Emit to server
socket.emit('some_event', ...etcetc);
}
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I am currently working on a game in which a timer will be needed, but the one made in js has a very long delay and on each device it is different, which in the case of a ranking where milliseconds count is unacceptable.
I want to create a stopwatch that will be synchronized with the server time and will have the smallest local delay and will show the elapsed time with an accuracy of 0.01 seconds. Any idea how i can do this?
My code look like this:
var stopper = setInterval(myTimer, 10);
let time = 0;
let run = true;
function myTimer() {
if(run) {
time += 0.01;
//update time display
}
}
You can keep something startTime on the server and use on the client to calculate passed time.
If you need to keep the time and update necessarily then try to use websocket
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I want to make a javascript timer for a countdown of 7 days since it is first run.
Here is the scenario:
The html file will given to 100 students
So the timer will start whenever one opens the html file
If the user restarts the computer the time will not affect
Dont know how its done..
The simplest possible JavaScript countdown timer?
This can be accomplished locally (that means that each user gets their own counter) by saving the value of Date.now() into localStorage. Then, when reopening the html file, you read from localStorage and compare the value to the current Date.now().
What you can do with this timer is then very limited, unless you serve this html file of yours from a server.
(function() {
var started = localStorage['started'];
if (started) {
// This is not the first time the user opens this file
// How long has it been?
var diff = Date.now() - started;
if (diff >= 1000 * 60 * 60 * 24 * 7) {
// At least one week has passed. Do something here.
} else {
// Less than a week has passed. Do something else here.
}
} else {
// This is the first time the user opens this file
localStorage['started'] = Date.now();
// Do something else here to welcome the user...
}
})();
Date.now reference: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/now
Just remember that there is no security at all in this. You are doing this on the user's browser, and the user has full control over that environment. A simple clear cache will delete the saved value from localStorage.
I have used this method to create a project time clock that runs completely locally.
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I don't know how to make a Javascript count up that is related to the real time, which means when you reload the page, the counter won't start over again. Would anybody tell me how to make that happen :) Example like http://www.worldometers.info/ Thanks a lot.
The code they are using is likely pulling from a database with an actual value increasing live.
Check out this js fiddle I made for an example of how a simple timer can work. Notice that if you press "Run" multiple times, the time itself will stay constant.
Using a remote database will cause a lot more work, but for saving values across browser refreshes you should learn about localStorage I'd check out W3 School's article on the subject.
In my implementation I use
localStorage.setItem("time", currentTime); // Note that CurrentTime must be a string!
in each iteration of your code after setting the currentTime var.
When you start up your application, a simple if statement
if (localStorage.getItem("time") {
CurrentTime = localStorage.getItem("time");
} else {
// set default values
}
will work, as localStorage.getItem will return null if the value doesn't exist (or if you set the value to null manually).
(for localStorage, you can also use [bracket notation] and will probably see that in most common examples)
localStorage["foo"] = "value";
// is the same as:
localStorage.setItem("foo", "value")
// and
var bar = localStorage["foo"];
// is the same as:
var bar = localStorage.getItem("foo");
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I want to perform a set timeout function with this behavior:
Apply focus to one object, after 10 seconds apply focus to another object, is that possible?
So I want to called it like
focustimeout([objectsarray])
where objectsarray is an array with all the id names for the N fields that I want to have a 10 second focus before each other.
I'm sorry for the question but in really new on javascript.
What can I add to this in order to get that solution
var temp = "id1";
var temp1 = "id2";
setTimeout(function(){
$("#"+temp).focus()
setTimeout($("#"+temp1).focus(), 10);
}, 10);
It's possible. Here is an idea how you can do it. Create function with 2 parameters, number of focused element and array of IDs which you want to focus.
function focus(i,array){
$("#"+array[i]).focus();
if(i<array.length){
setInterval(function(){focus(i++,array),yourTime);
}
Then call it from beginning focus(0,array)