New to javascript here.
The Team Treehouse blog has a small tutorial on how to build a timer in javascript. It is basically the following code:
<h1 id="timer">Loading</h1>
var updateMessage = function(){
var date = Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
var timer = setInterval(updateMessage, 500);
This works fine and all. However I want to use date for multiple functions. I tried the following..
var date = Date();
var updateMessage = function(){
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
..but now it doesn't work realtime. Whenever I hit F5 it gives back the correct time but it's not updated realtime anymore.
Why is this? I thought that when I declare a variable outside of a function, it would become a global function which could be used anywhere.
Because Date() is the time you call it, it does not keep updating!
If you want to share it, update it inside of the function.
var date;
var updateMessage = function(){
date = new Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
var date = Date();
var updateMessage = function(){
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
in above case var date is a variable whose value is assigned when script loaded.
and in another case var date is assign all time when the updateMessage is called
var updateMessage = function(){
var date = Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
var date = Date();
Is only executed once when script loads. The variable date stays the same throughout the lifetime of the webpage. That is why it only changes when you refresh the page.
The problem here is not where you define the date variable but where and how many times you are calling the Date() function.
Declaring it globally but making the necessary call everytime you need is also a valid solution.
var date; // declaration
var updateMessage = function(){
var message = document.getElementById("timer");
date = Date(); // call to Date() everytime updateMessage is executed
message.innerHTML = "The time is " + date;
}
Well you are missing setInterval in second example?
Apart from that, you were on the right track, but with a little problem: The way you are doing it now, you are getting the Date() when you load the page, and just use the same date over and over.
Something like this should work for you, as it would give you a global variable while changing the date dinamically:
var date = Date();
var updateMessage = function(){
date = Date();
var message = document.getElementById("timer");
message.innerHTML = "The time is " + date;
}
Related
I am currently working with a javascript that is supposed to remove some unwanted cookies, but for some reason aren't they removed when told to?..
only after certain amount of times trying to remove them, they seem to be removed.. some sort of delayed effect?
here is the code:
const name = 'test_u';
const name1 = 'test_te_s';
function eraseCookie(name) {
document.cookie = name+'=; Max-Age=-99999999;';
}
function removeCookies(cookieA, cookieB) {
setInterval(function() {
if (document.cookie.includes(cookieA) || document.cookie.includes(cookieB))
{
eraseCookie(cookieA);
eraseCookie(cookieB);
var date = new Date();
var timestamp = date.getTime();
console.log(timestamp)
}
},10000);
}
removeCookies(name, name1);
example from console log output:
1555420706478
1555420716477
1555420726487
1555420736487
1555420746497
1555420756487
It runs 6 times before its removed? but why though?
why aren't they removed immediately?
Because you have setInterval which means that that code will be run after some time that you provide, and keep repeating it by that interval. So just remove that setInterval:
function removeCookies(cookieA, cookieB) {
if (document.cookie.includes(cookieA) || document.cookie.includes(cookieB)) {
eraseCookie(cookieA);
eraseCookie(cookieB);
var date = new Date();
var timestamp = date.getTime();
console.log(timestamp)
}
}
And if you want to keep repeating it try this one:
removeCookies(name, name1);
setInterval(() => {
removeCookies(name, name1);
}, 10000);
or
function removeCookies(cookieA, cookieB) {
if (document.cookie.includes(cookieA) || document.cookie.includes(cookieB)) {
eraseCookie(cookieA);
eraseCookie(cookieB);
var date = new Date();
var timestamp = date.getTime();
console.log(timestamp)
}
setInterval(() => {
removeCookies()
}, 10000);
}
removeCookies(name, name1);
so it will first call removeCookies, and then it will keep repeating.
Here is a very simple program that I wrote:
function () {
var app = SpreadsheetApp ;
var tableur = app.getActiveSpreadsheet() ;
var feuille = tableur.getActiveSheet();
var now = new Date();
Utilities.sleep(900000)
feuille.getRange("A1000").setValue(now);
feuille.getRange("B1000:O1000").setValue("1000000");
feuille.getRange("P1000").setValue("Prudent");
feuille.getRange("Q1000").setValue("10");
feuille.getRange("R1000").setValue("10");
feuille.getRange("S1000").setValue("NON");
}
However, I want the code to wait 15 minutes before it continues. Google has a restriction of 5 minutes, which is why I read a lot about this issue but I couldn't find any solution. I actually used Utilities.sleep (900000) but it doesn't work.
I appeal to your kindness to explain to a beginner like me how to circumvent the restriction if ever this is possible! :)
function onEdit(e) {
var triggerTime = new Date();
var scriptProperties = PropertiesService.getScriptProperties();
scriptProperties.setProperty("lastTrigger", triggerTime);
}
function doSomething() {
var scriptProperties = PropertiesService.getScriptProperties();
var lastTrigger = new Date(scriptProperties.getProperty("lastTrigger"));
var lastTriggerUnix = lastTrigger.getTime() / 1000; // using unix time for a more straightforward time comparison
var nowUnix = (new Date()).getTime() / 1000;
var FIFTEEN_MINUTES = 15 * 60;
if ((nowUnix - lastTriggerUnix) >= FIFTEEN_MINUTES) {
scriptProperties.deleteProperty("lastTrigger");
var app = SpreadsheetApp ;
var tableur = app.getActiveSpreadsheet() ;
var feuille = tableur.getSheetByName("Réponses"); // getActiveSheet() can yield unexpected results
var app = SpreadsheetApp ;
var now = new Date()
feuille.getRange("A10").setValue(now);
feuille.getRange("B10:O10").setValue("1000000");
feuille.getRange("P10").setValue("Prudent");
feuille.getRange("Q10").setValue("10");
feuille.getRange("R10").setValue("10");
feuille.getRange("S10").setValue("NON");
}
}
Is there something I forgot?
Given the new information that you want the doSomething() script to run roughly 15 minutes after the spreadsheet was last edited, here's my modification, but using the same general principle.
Create an onEdit() simple trigger that saves the edit time to the Properties Service (this is done by simply including the onEdit function, which Google interprets automatically). Separately, create a manual trigger to run the doSomething() function every 5 minutes or so. When that function runs, it will check the last edit time and execute your desired actions if the difference between the last edit and now is greater than or equal to your desired length.
function onEdit(e) {
var triggerTime = new Date();
var scriptProperties = PropertiesService.getScriptProperties();
scriptProperties.setProperty("lastTrigger", triggerTime);
}
function doSomething() {
var scriptProperties = PropertiesService.getScriptProperties();
var lastTrigger = new Date(scriptProperties.getProperty("lastTrigger"));
var lastTriggerUnix = lastTrigger.getTime() / 1000; // using unix time for a more straightforward time comparison
var nowUnix = (new Date()).getTime() / 1000;
var FIFTEEN_MINUTES = 15 * 60;
if ((nowUnix - lastTriggerUnix) >= FIFTEEN_MINUTES) {
scriptProperties.deleteProperty("lastTrigger");
// Do what you need to do here
}
}
You should use the Properties Service to save now, then use a Trigger to run the script every 15 minutes. (The first time you run it, the timings might be slightly off.)
function doSomething() {
var app = SpreadsheetApp ;
var tableur = app.getActiveSpreadsheet() ;
var feuille = tableur.getSheetByName("Sheet2"); // getActiveSheet() can yield unexpected results
var scriptProperties = PropertiesService.getScriptProperties();
var storedNow = scriptProperties.getProperty("now") || new Date(); // Get the stored time. If it doesn't exist, create a new one.
var now = new Date(storedNow); // The value is stored as a String in the Properties Service, so convert to Date.
feuille.getRange("A10").setValue(now);
feuille.getRange("B10:O10").setValue("1000000");
feuille.getRange("P10").setValue("Prudent");
feuille.getRange("Q10").setValue("10");
feuille.getRange("R10").setValue("10");
feuille.getRange("S10").setValue("NON");
now = new Date(); // Create a new date to be used when the function runs again
scriptProperties.setProperty("now", now); // Save the new date
}
As noted in the trigger documentation, you can create the trigger from the Edit menu > Current project's triggers.
I tested this on a 5-minute interval and received the below outputs. As I manually ran the function the first time, its time value is not consistent with the subsequent iterations.
4/6/2018 10:32:15
4/6/2018 10:33:32
4/6/2018 10:38:32
4/6/2018 10:43:32
4/6/2018 10:48:32
I have written following code for getting daily recurrence in my angular, my issue is when I use byweekday property of RRule JS, application stuck and does not respond at all. Sometimes it does work but takes huge time to execute code on line #rrule_after. Please let me know why is this happening and what can be better solutions for this?
function getNextRecurrenceDate(recurrenceVo,rule){
var startDate = new Date(recurrenceVo.recurrenceRangeVO.startDate);
var today = new Date();
var calculatedDate = null;
if(today.getTime() <= startDate.getTime()){
return startDate;
}else{
//#rrule_after - when I debug the code and comes to this function execution, my application stucks/halts for long time and does not response at all
calculatedDate = rule.after(today,true);
// this is temporary code I have written to overcome the problem of daily weekday recurrence
if(calculatedDate && recurrenceVo.dailyRecurrenceVO && recurrenceVo.dailyRecurrenceVO.everyWeekDay && calculatedDate.getDay() > 4){
calculatedDate.setDate(calculatedDate.getDate() + (7 - calculatedDate.getDay()));
}
}
return (calculatedDate)?calculatedDate:'';
}
function getDailyNextRecurrenceDate(recurrenceVo){
var rule = new RRule({
freq: RRule.DAILY,
interval: recurrenceVo.dailyRecurrenceVO.numberofDays,
dtstart: new Date(recurrenceVo.recurrenceRangeVO.startDate)
})
if(recurrenceVo.recurrenceRangeVO.endCount){
rule.options.count = recurrenceVo.recurrenceRangeVO.endCount;
}
if(recurrenceVo.dailyRecurrenceVO.everyWeekDay){
rule.options.interval = 1;
// When I remove this code then all working fine and application not halting at all
rule.options.byweekday = [RRule.MO, RRule.TU, RRule.WE, RRule.TH, RRule.FR]
}
if(recurrenceVo.recurrenceRangeVO.endDate){
rule.options.until = new Date(recurrenceVo.recurrenceRangeVO.endDate);
}
var nextRecDate = getNextRecurrenceDate(recurrenceVo,rule);
return nextRecDate?nextRecDate.setHours(0,0,0,0):'';
}
It's actually a follow up to this question I want to display elements from json based on their time and duration and interval is interupted by settimeout - I accepted the answer there made by #Daniel Flint - his code is quite clear and can be found here http://jsfiddle.net/nauzilus/rqctam5r/
However, there's one more thing that I wanted to add - a simple div <div id="time"></div> that would contain a new date time object initialized during opening the page and then it being incremented every second just to show the current time constantly. I thought about writing there a javascript:
var actualTime = new Date(substractedDate); // taken from the server
function updateTimeBasedOnServer(timestamp) {
var calculatedTime = moment(timestamp);
var dateString = calculatedTime.format('h:mm:ss A');
$('#time').html(dateString + ", ");
};
var timestamp = actualTime.getTime();
updateTimeBasedOnServer(timestamp);
setInterval(function () {
timestamp += 1000; // Increment the timestamp at every call.
updateTimeBasedOnServer(timestamp);
}, 1000);
(I provide the time of the server as a timestamp there).
I just noticed that there is a slight mismatch between displaying the time in my div and between the text appearing on the screen, possibly because I increment both of the values in two different places.
So my question is - how can I "merge" #Daniel Flint's code with mine and increment both values only in one place?
One thing that jumps out here:
timestamp += 1000;
setTimeout/setInterval aren't guaranteed to run at precisely the delay you've entered. Run this in your browsers console:
var last = Date.now(),
time = function() {
var now = Date.now();
console.log(now - last);
last = now;
},
id = setInterval(time, 1000);
On my Mac at home (Chrome/FireFox) it was anywhere from 990 to 1015. Windows machine at work is a bit better (995-1002), but IE was getting up to 1020. It's not a huge difference, but it's not nothing.
So code needs to be able to handle not running exactly every 1000ms. That's why I was running the timer at 500ms intervals, and checking if the start time was less-than-equal to the current time.
I've rejigged the demo to show the time and message in sync:
(function() {
var messages = [];
var time = document.getElementById("current-time");
var display = document.getElementById("message");
function check() {
showMessage(currentMessage());
showTime();
}
function currentMessage() {
var message = null;
if (messages.length) {
var now = toTheSecond(new Date());
var start = toTheSecond(new Date(messages[0].start_time));
var end = toTheSecond(new Date(start.getTime() + ( messages[0].text_duration * 1000 )));
if (start <= now) {
if (end <= now) {
// done with the current message...
messages = messages.slice(1);
// ...but check if there's another one ready to go right now
message = currentMessage();
}
else {
message = messages[0];
}
}
}
return message;
}
function toTheSecond(date) {
date.setMilliseconds(0);
return date;
}
function showMessage(message) {
if (message) {
display.textContent = message.text_content;
}
else {
display.textContent = "no messages";
}
}
function showTime() {
time.textContent = new Date().toLocaleString()
}
function getMessages() {
setTimeout(function() {
var now = new Date();
messages.push(
{"text_content":"aaaaa","text_duration":5,"start_time": new Date(now.getTime() + 3000).toISOString()},
{"text_content":"aawwaaaaa","text_duration":5,"start_time": new Date(now.getTime() + 10000).toISOString()},
{"text_content":"bbaawwaaaaa","text_duration":5,"start_time": new Date(now.getTime() + 15000).toISOString()}
);
}, 1000);
}
setInterval(check, 500);
getMessages();
})();
<span id="current-time"></span> <span id="message">Hello there!</span>
(Putting the code here as well because I recall SO want code in the answers so it's controlled, but there's a demo here: http://jsfiddle.net/nauzilus/ymp0615g/).
This probably isn't as efficient as it could be; the message text is being set every iteration which might cause repaints/reflow. But then again setting the time stamp is going to do that anyway, so meh :)
I want to format the date right but get an error message when i try it.
My code:
var dateText = document.getElementById("text");
var dateDiv = document.createElement("div");
dateDiv.id = "tid";
dateDiv.innerHTML = MessageBoard.messages[messageID].getDateText();
text.appendChild(dateDiv);
And in another .js file:
this.getDate = function() {
return date;
};
this.setDate = function(_date) {
date = _date;
};
/.../
Message.prototype.getDateText = function() {
return this.message.getDate().toLocaleTimeString();
};
But i got an error message that says: "Uncaught TypeError: Cannot call method 'getDate' of undefined"
To get the date with just getDate works fine.
This is just a guess, since you didn't post enough code to tell for sure:
return this.getDate().toLocaleTimeString();