javascript countdown timer minutes seconds codepen

We need to make the clock script more efficient. * done! Edit: Note, this doesnt do any input checking (like if delay and repeat are the correct type. on return add the hours value. All it does is decrement the remaining seconds by 1, then update the HTML. Following points outlined above the snippet implements a countdown timer with start/restart and stop buttons. Make a . We used prompt function to ask the user for birth date and birth month. On eCommerce websites, you can use a countdown timer to display the beginning (or the end) of an offer. A former hardware technician, and network administrator. Many of these answers here are great, but they typically their code examples are pages and pages of code (the good ones even have instructions on the best way to copy/paste it all). As noted above, it is possible to include times and time zones, but I used plain dates here to keep the code readable. The purpose of the countdown timer is to urge customers to take actions such as buying products or services. It looks like our animation is lagging by one second. Heres a solution that pauses when the window is hidden, and can be cancelled with an abort controller. Then add the following to the initializeClock function (after the line that begins with var clock). DigitalOcean provides cloud products for every stage of your journey. let seconds = time % 60; if (seconds < 10) { We have a method that starts the timer but we do not call it anywhere. Next, lets create an initial color for the remaining time path. Taking just 10 samples with this method makes a reasonable difference. //the final date const fest = new Date(2022, 3, 2); // the system date const current = new Date(); //time remianing const sec = (fest - current) / 1000; Using my timer function, IDK about you, but for me at least the curried version is way more readable and this is more noticeable if we have several timers with the same hour running in different parts of the DOM at the same time: To be honest, it gives the impression that the author simply enjoys writing idiosyncratic code (which is confirmed by your statement about classes and the fact that you created an array just to be able to use map), Ad hominem doesn't make you right, and "creating an array just to use map" what? Can you please update the complete answer. What do I have to do remove the minutes and the : when under 1 minute is left? It may be necessary to set a countdown for a given amount of time after the user arrives or starts a specific task. Returns the frame index for the next frame (the cancelled frame). We said we wanted to change the color of the progress indicator when when the time remaining reaches certain points sort of like letting the user know that time is almost up. Duration Between Two Dates - Calculates number of days. Heres the demo again with everything put together. Calculates the difference between the initial time remaining and how much time has passed, Changes color as the time remaining nears zero, Displays the progress of time remaining as an animated ring, Remove the fill and stroke from the circle wrapper element so we get the shape but let the elapsed time show through. I need multiple timers on one page, and each one to start on a click action. weight on the outlier. To learn more, see our tips on writing great answers. The Date.parse() function converts a time string into a value in milliseconds. Save my name, email, and website in this browser for the next time I comment. Fifth, when the countdown completes, it shows a message e.g., "Happy New Year". For example: after 61 seconds, the second unit shows 1 again, and the minute unit goes up. Asking for help, clarification, or responding to other answers. I agree with Bergi on using Date, but his solution was a bit of overkill for my use. Here it is with those fixes and some more: What's the purpose of returning a function by your timer function instead of using 2 arguments? The time remaining on your countdown timer is all set. Lets start with creating a basic template for our timer. The complete() method checks if the onComplete callback is passed and invoke it. Now, lets create a method thats responsible for checking if the threshold exceeded and changing the progress color when that happens. The interface can be customized according to . This article is contributed by Shubrodeep Banerjee. Yikes, this looks very complicated, but keep calm and look carefully. Next: Write a JavaScript function to get time differences in hours between two dates. Output the clock data as a reusable object. Ex: var offerDate = new Date(2021,09,16,09,20,0,0) Set the values ten minutes ahead of current time to acheive 10 minutes countdown timer. The reason is because of the interval of 1 sec. This allows us to subtract two times from each other and get the amount of time in between. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. Sign in to view all comments. And youll learn how to use it to build a New Year countdown timer. Regards, Nuno, This comment thread is closed. If we wanted to set a 10-minute timer across the site, we wouldnt want it to reset when the user goes to a different page. 1-9). The important thing here is to make sure the stroke-width is the same size as the original ring and that the duration of the transition is set to one second so that it animates smoothly and corresponds with the time remaining in the time label. Right now one minute is equal to 60 seconds so in this case we have divided by 1000 * 60. In this folder create 3 files: Second, download birthday celebration image to this project folder which will be used for the background of the birthday countdown. 2) As described in section B Just set counter.end = Date.UTC(2020, 0, 1, 0, 0, 0); You may shorten the code if you wish. Perhaps you just have a hard time believing someone can master and enjoy functional programming without becoming anal about it and wanting to use it absolutely everywhere or imposing it to other programmers. 3) Create an HTML audio tag , play sound when time is 0 or less if (counter.end <= 0) { document.getElementById("alarm-sound").play(); }, HTML Audio Tag reference - https://developer.mozilla.org/en-US/docs/Web/HTML/Element/audio, Your email address will not be published. There is still a small but in that the ring doesnt appear to start moving until the countdown reaches 00:19. One of my simplest implementations is down below. Responsive: Yes. day, hours, minutes, seconds, milliseconds) . You may have an event, a sale, a promotion, or a game. Lastly, I have instructed to update this calculation every 1000 milliseconds using setInterval. Returns the implied interval in milliseconds. Lets see how our ring will look like with different stroke-dasharray values: What we can see is that the value of stroke-dasharray is actually cutting our remaining time ring into equal-length sections, where the length is the time remaining value. Second, create the style.css in the css folder, app.js and countdown.js files in the js folder, and the index.html in the countdown-timer folder: Third, download this firework picture and copy it to the img folder. Source: Codepen.io. Above we have done all the work of calculation, now we will arrange it neatly in the web page. the condition from the startTimer() function (so the timer never stops and goes to negative values) or setting the FULL_DASH_ARRAY constant. Nilson is a full-stack web developer who has been working with computers and the web for over a decade. I guess it all depends on person preferences and what people are used too. Note that the countdown.js file must appear before the app.js file because the app.js will use the objects in the countdown.js file. If code_mystery is not suspended, they can still re-publish their posts from their dashboard. Third, use CSS flexbox to set the countdown app to the centre of the screen by selection class 'countdown-timer'. seconds = 0${seconds}; A countdown timer is a clock running on any landing page with decreasing time on it. What the JavaScript code does is, it converts the days, hours and minutes to seconds and adds everything together. Like this: return ${minutes}:${seconds.toString().padStart(2, '0')}; I thought this would be a good candidate for converting to a custom element, so I tried. The last element is a paragraph element with class name 'coming-year', which will be used to show coming birthday year in the background. While using W3Schools, you agree to have read and accepted our. Then add a new component named count-down which will contain the logic for our countdown . Try adding some creative styles, or new features (such as pause and resume buttons). It represents a single moment in the time. 1. Lets first add a path element in our SVG element. To correct it, you can keep track of the drift history and use it to predict future drift. Do, JavaScript countdown timer for hour, minutes and seconds when a start button click, w3schools.com/howto/howto_js_countdown.asp, Flake it till you make it: how to detect and deal with flaky tests (Ep. I created that box using the code below. Sooo Ive wrapped it up into a constructor function so we can do objecty things with it. Get started with $200 in free credit! Here's my take. One way to accomplish this is to put each number inside a span tag and only update the content of those spans. We collect information about the use of our website. To convert milliseconds to seconds divide it by 1000. That should be good.. @JDrake corrected the mistake. const FULL_DASH_ARRAY = 283; Hi, What's the term for TV series / movies that focus on a family as well as their individual lives? Summary: in this tutorial, youll learn how to develop a reusable JavaScript countdown timer. When that reaches 0 it will start another timer and display the text 'On Window'. However, sometimes you really need a steady interval executing your callbacks without drifting. To implement this, replace the deadline variable with the following: This code makes use of cookies and regular expressions, both of which are separate topics in their own right. It can even survive page reloads. While creating countdown time you will have to calculate remaining days, hours, minutes and seconds to display it on screen. Leaving it as timeLeft / TIME_LIMIT works perfectly. Why does secondary surveillance radar use a different antenna design than primary radar? Then base your logic on the current time value, instead of counting how often your callback has been executed. Lets think about what we need to count down the time. Tip: Learn more about the window.setInterval() method in our JavaScript Reference. How to count each hour,min and sec. Use the Date object instead to get the (millisecond-)accurate, current time. As you probably noticed, the template includes an empty thats going to hold the time remaining. When it reaches 10 seconds the circle should be in the middle. This function will do the following: At this point, the only remaining step is to run the clock like so: Congratulations! Your email address will not be published. However, there is a little bug that I cant solve. Then we worked on HTM, CSS and JavaScript code of Countdown timer app. The following getTime() method returns an object that contains the remaining days, hours, minutes, and seconds based on the timeRemaining property. Heres an example of how youd get the remaining minutes: Now that we have a function that spits out the days, hours, minutes, and seconds remaining, we can build our clock. This is fine if you just need accurate intervals, but if you are timing relative to other events then you will (nearly) always have this delay. By using our site, you You can also find Nilson on the SitePoint Forums as a mentor. function countdownTimer {const difference = + new Date ("2020-01-01")-+ new Date (); let remaining = "Time's up!". Makes life easy, import the npm package, then use it like setInterval / setTimeout: you can use a function called setTimeout that we can use to set the countdown. For example: Each of these formats allows you to specify an exact time and a time zone (or an offset from UTC in the case of ISO dates). A countdown timer is an accurate timer that can be used for a website or blog to display the count down to any special event, such as a birthday or anniversary.Basics of a countdown timer are : Step 1 : Set a Valid End DateThe Valid end date and time should be a string in any of the formats understood by JavaScripts Date.parse() method. You need a counter for seconds. Kyber and Dilithium explained to primary school students? We include countdown.js which we will made in next step.You may also like session timeout warning with countdown using PHP and jQuery . You can use the CSS from another Pen by using its URL and the proper URL extension. If a deadline was recorded in a cookie, use that deadline. function startTimer(duration, display) { var timer = duration, minutes, seconds; setInterval(function { minutes = parseIn. As you can see in the picture above I have used the web page background # 90cbf3 here. hi for some reason it just seems not to be working.. firstly the FULL_DASH_ARRAY isnt defined and the animation isnt working too, After the countdown, is it possible to add download button to it that will be reveal after it reached zero. A countdown timer is a virtual clock running on a landing page. Example: Additionally, you dont need the fix at calculating the time fraction. What does and doesn't count as "mitigating" a time oracle's curse? You can change your preference here. Use the Date object instead to get the (millisecond-)accurate, current time. During each 1 second interval, decrement this counter, and do the necessary calculations. Is this possible to add when a button click? The code. We also need to update our path each second that passes. We are a team of skilled designers, developers, and analysts who know how to turn great ideas into even better end products that engage users and grow your business. Your clock is now ready for display. The following defines a function that hides the greeting message and shows the heading element: Seventh, define a complete() function that shows the message for a period of time and then hides it. Welcome to a tutorial and example on how to create a simple Javascript Countdown Timer. This looks intimidating again, but just take a minute to study the code. Now that we are done with the basic usage, here are more details on how the countdown timer works. (If It Is At All Possible). Those are known as self-adjusting timers. Something like this. And today we are going to make a countdown timer with javascript. Is this a direction I should consider for this task. Next, we need to alter the updateClock function to update only the numbers. Or a timer for an offer? 528), Microsoft Azure joins Collectives on Stack Overflow. First we calculate the time remaining by subtracting the deadline by current date and time then we calculate the number of days,hours,minutes and seconds.The . @ChathuriFernando Updated the answer with the code snippet. If the user switches tabs and back, an average would put far too much Set an initial value for a Javascript Count Down Timer, Lots of seconds get skipped in countdown timer script, Use current time and count down to hour and reset to next hour countdown, Javascript "clearInterval" method cannot stop the timer when defined outside of window.onload, CountDown Timer with start/Pause and reset button, Looking to protect enchantment in Mono Black. : to execute the complete() or start() method based on the value of the this.timeRemaining property. Just put a URL to it here and we'll apply it, in the order you have them, before the CSS in the Pen itself. Is there a function to add that will just show zeros? You create project folder will look like this: The HTML code for the countdown timer is quite simple. There are several functions that work together to handle all the functions of the timer. Just looking to be pointed on a direction for research. The project structure will look like this: The HTML page is quite simple because youll generate most of the HTML code from JavaScript. Comes in handy. */, // don't update the history for exceptionally large values, // sample drift amount to history after removing current correction, // (add to remove because the correction is applied by subtraction), // take into account drift with prediction. Improve this sample solution and post your code through Disqus. */, /** Source Download. When we reach 0 a small piece of the ring is still visible. Lets move the anonymous function that were passing to setInterval into its own separate function. Here is the snippet of code I put in my clock update functions: It simply calculates the delta time to the next even second, and sets the timeout to that delta. How can I apply this for count hour,min and sec. For further actions, you may consider blocking this person and/or reporting abuse. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Since one hour is equal to 60 minutes, in this case we have divided by 1000 * 60 * 60. Site Maintenance- Friday, January 20, 2023 02:00 UTC (Thursday Jan 19 9PM Were bringing advertisements for technology courses to Stack Overflow, Alert box appears repeatedly and does not allow user input, Run a javascript script when a button click is not working, Trigger a button click with JavaScript on the Enter key in a text box, Javascript seconds to minutes and seconds, How to trigger a file download when clicking an HTML button or JavaScript. For example, if youre always getting a drift of 20 to 40ms, this adjustment would shift it to -10 to +10ms around the target time. When the interval lags a bit and executes your callback after 990, 1993, 2996, 3999, 5002 milliseconds, you will see the second count 0, 1, 2, 3, 5 (!). And youd probably want to add some kind of get/set function if you wanted to get the count or change the repeat value. callback. Home JavaScript DOM JavaScript Countdown Timer. Thats it for all the code and examples, and here are some extras that may be useful to you. As a new user you might not know is not ok to write comments only to be confrontational, so I'll suggest to lower that a notch. To animate the length of the remaining time line we are going to use the stroke-dasharray property. Source code is given. Can I (an EU citizen) live in the US if I marry a US citizen? $ cd count-down-timer. Code Boxx participates in the eBay Partner Network, an affiliate program designed for sites to earn commission fees by linking to ebay.com. JavaScript countdown timers are used on a variety of e-commerce and under-construction websites to keep users up to date. We looked at few properties of Date object, how to get time and number of milliseconds ellapsed and then difference between 2 moments of time. Let us walk through one in this guide Read on! 1) Just put a image tag below the countdown timer? The countdown timer will display four figures: days, hours, minutes, and seconds. All we need to do here is replace the deadline variable with this: This code takes the current time and adds ten minutes. It will become hidden in your post, but will still be visible via the comment's permalink. 8-10 Greatorex StreetLondon E1 5NF, United Kindom, 2021 EssentialWebApps. My approach takes the original 4 values and maps them into the quadruple. You can wrap the logic inside an other object with getters/setters or whatever you prefer. Display the clock on the page, and stop the clock when it reaches zero. The website will perform better because there wont be any need of loading external scripts and style sheets. If I have done anything wrong, please let me know in the comments. The tutorial misses the definition of FULL_DASH_ARRAY so the green progress never moves. I mean, it works for me anyway. First well create the following HTML element to hold our clock: Then well write a function that outputs the clock data inside our new div: This function takes two parameters.

Comment . Any thoughts on a direction on how to incorporate a remote control for this using a phone? Sometimes its necessary to preserve the state of the clock for more than just the current page. The following code show how to create a new Date object that represents the current date and time: Now let's see how to get milliseconds elapsed since a date and time. We need to write a function that takes a string representing a given end time (as outlined above). const minutes = Math.floor(time / 60); I hope this helps someone. The following defines a new method called setExpiredDate() that initializes the timeRemaining property: If the timeRemaining is greater than zero, the setExpiredDate() method will execute the start() method to start the timer. After working through the examples in this article, you now know how to create your own countdown timer with just a handful of lines of vanilla JavaScript code! * Self-adjusting interval to account for drifting We see on different types of e-commerce websites that a kind of countdown starts some time before the arrival of any product or offer. You just need to define deadline in the timer function call and this code snippet start countdowns from that time. * the difference in days, hours, minutes and seconds. You can also easily extend this to include days or weeks: Your code does suffer from one downside: if for some reason the calls become slightly further apart, this might increasingly build a delay. Most upvoted and relevant comments will be first, I moved away from DEV for blogging, so now I'm barely active here. With background # 90cbf3 you can use any other color you want. When that timer proceeds to reach 0 it will end until I start it up again by setting a date in the file. acknowledge that you have read and understood our, Data Structure & Algorithm Classes (Live), Full Stack Development with React & Node JS (Live), Data Structure & Algorithm-Self Paced(C++/JAVA), Full Stack Development with React & Node JS(Live), GATE CS Original Papers and Official Keys, ISRO CS Original Papers and Official Keys, ISRO CS Syllabus for Scientist/Engineer Exam. Would need to be able to start, stop/pause, resume in what Ive seen called lags, each start and stop report the length of time and giving the balance of time. countdown javascript. Third, use CSS flexbox to set the countdown app to the centre of the screen by selection class 'countdown-timer'. Display the clock on the page, and stop the clock when it reaches zero. Thank you for reading, and we have come to the end of this short guide. That means we need to call the newly created setCircleDasharray method inside our timerInterval. Here is the final birthday countdown timer you are going to make. Hope you will like it.subscribe and turn on the no. Heres how to schedule things in advance. Now we have a timer that starts at 20 seconds but it doesnt do any counting just yet. For example: To get the remaining minutes (2), you use the Math.floor() function: To get the remaining seconds (30), you use the modulus operator( % ) that returns the division remainder: First, create a new CountDown class in the countdown.js file: The CountDown class should be initialized with three arguments: The constructor of the CountDown class will look like this: Based on the expiredDate argument, you can calculate the remaining time in milliseconds: Since youll need to access the remaining time (timeRemaining) across methods of the class, you should define it as a property of the CountDown class. Now you can schedule your clock in advance without having to update it by hand. This will output a stroke that covers the timer ring like it should, but it doesnt animate just yet to reveal the timer ring as time passes. Based on the stroke-dasharray setting, I created the variable (placed on the line under the other const variable TIME_LIMIT). 3. Im talking about the 3-countdown that shows hours/minutes/seconds. but not working. Soon we'll even get the pipe operator, which makes the use of curried functions even more readable. calculateTimeFraction(timeLeft, timeLimit) * FULL_DASH_ARRAY Use Math.floor to convert it to an integer. Is it possible to calculate timer in terms of working days? Lets make one together! If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to [email protected]. To make your timer more accurate, you would have to round. All I did was copy the code from the link above, modified it for a button handler, and pasted it. On eCommerce websites, you can use a countdown timer to display the beginning (or the end) of an offer. Were starting with green, then go to orange as a warning, followed by red when time is nearly up. clearInterval() Simple, short, readable, and unpretentious: Some comments may only be visible to logged-in visitors. I simply wanted my animated clock (digital and analog SVGs) to update on the second and not overrun or under run creating obvious jumps in the clock updates. Each time the setInterval function deducts a second, the remaining seconds are converted back to days, hours, minutes and seconds using the convert . As for your other changes I wanted to explain the very same things and couldn't agree more. The following shows the final New Year countdown landing page. Examples might be simplified to improve reading and learning. In most cases, this wont matter. That way, navigating to a new page wont reset the end time to ten minutes from now. * @param {number} future Lets create it and set the initial value to our time limit. Voil, there we have it. Bergis answer pinpoints exactly why the timer from the question is not accurate. Experts I need to send an email that basically shows some text with a countdown timer showing how much time is left. This is the day-5 of #30days30submits. It will be a birthday countdown which will indicate how much time left to your next birthday. Need to do a countdown for the launch of an event, store, or product? Building the countdown timer. Yes, it is possible with Javascript - Check out Breakthrough Javascript! if(typeof ez_ad_units!='undefined'){ez_ad_units.push([[300,250],'tutorialstonight_com-medrectangle-4','ezslot_4',624,'0','0'])};__ez_fad_position('div-gpt-ad-tutorialstonight_com-medrectangle-4-0');The countdown timer can also indicate how much time left to some event. Of course it is possible to bind it to a button. Why is 51.8 inclination standard for Soyuz? You might instead want to use the lines: check your console. Lets implement a method called startTimer that will: We also need to keep the reference to that interval object to clear it when needed thats why we will create a timerInterval variable. We use the Google Analytics cookies to track visitor behavior and measure our website performance. Start by declaring an empty function called startCountdown that takes seconds as an argument: We want to keep track of the seconds that pass once the timer is started, so use let to declare a variable called counter and set it equal to seconds: function startCountdown (seconds) { let counter = seconds; } FYI your code pasted in with a space between < and = which would cause an error. How hard would it be to adjust it so that it displays: // duplicate minutes and call it hours. However in my opinion your syntax to start the timer kinda looks ugla to be to be honest. var x = setInterval (function() {. How to rename a file based on a directory name? Let's start with the HTML. For in-depth JavaScript knowledge, read our book, JavaScript: Novice to Ninja, 2nd Edition. Create a < span> element for each so that later you can target them with JavaScript. The method name in step 2 doesnt match the method name in the template in step 2. I love Haskell too, but I'm not a big fan of its ecosystem, not to mention its namespace problem for records. Lets see how it looks. To do that we will create a method called formatTimeLeft: Then we will use our method in the template: To show the value inside the ring we need to update our styles a bit. One simple way to do this is to add a string of 0 to the beginning of a number and then slice off the last two digits. This is due to the animations duration being set to one second. What we need initially is for the ring to cover the full length of the circle, meaning the remaining time equals the length of our ring. You can apply CSS to your Pen from any stylesheet on the web. I disagree. As in the countdown timer (year, day, month, hours and seconds), add a gif picture. Please enable Strictly Necessary Cookies first so that we can save your preferences! The other answers seem to use this approach, but I wanted a compact explanation. You can manage your cookie settings below. Then base your logic on the current time value, instead of counting how often your callback has been executed. Now at the end of it all I will design the text that I added using the span in the JavaScript code. Because you are using setTimeout() or setInterval(). *. The same happens with timer, you can start the timer with any date compared to now, and then set as many elements as you want to have the same timer on it, not just one :D. As you can see, we have a pattern that keeps on repeating. Great Aritcle, It is good to clear the timer of the interval using Involves Javascript. I mapped the different time values to their diff equivalents, and is what map is good for a -> b kinda makes your initial quote about loving Ocaml, Haskell and F# look like you actually googled what currying is before writing your comment and found those programming languages. Well want to update only the numbers in the clock instead of rebuilding the entire clock every second. This is fine most of the time, except in the beginning when there will be a one-second delay. Can you make a countdown timer in pure CSS? Good luck and happy coding! OK, we are ready to play with the timeLeft value, but the value doesnt exist yet. And it counts down from a certain date to indicate the beginning (or the end) of an event. As a result, I have got a total of how much time to countdown. Right on! W.S. All Rights Reserved, Hooray! Latest & unique collection of hand-picked JavaScript Countdown examples with codes and previews. I need to create a simple but accurate timer. Used by online commerce websites to display time left for an ongoing sale. With the days, hours, minutes, and seconds prepared, were now ready to return the data as a reusable object: This object allows you to call your function and get any of the calculated values. This code should replace the previous call to the initializeClock function. Required fields are marked *. To convert milliseconds to minutes divide it by 1000 * 60. Get certifiedby completinga course today! Then, with the help of JavaScript code, subtracting the current time from that time, the subtraction is reduced every second. const circleDashArray = ${( Watch Live Preview JavaScript Countdown Timer. For a simple timer or clock, keep track of the time difference explicitly: Now, that has the problem of possibly jumping values. Then use modulus operator (%) and take modulus at 60 to get seconds in range 0-60. Good time of day! The name dasharray suggests that we can set multiple values as an array. countdown timer javascript; while loop countdown javascript; js countdown seconds; javascript days countdown; var countdown = function(num) {} count up timer javascript; TPC Matrix View Full Screen. Then using the new Date () method I have taken the current time from the device. I just wanted to understand this problem with a very simple example. The question should be more like "I don't get the advantage over calling one single method with multiple arguments" as it requires less memory in larger scales. That sets the first section (remaining time) length to 10 and the second section (passed time) to 30. // Using sessionsStorage to make the timer persistent, "https://cdnjs.cloudflare.com/ajax/libs/jquery/1.12.4/jquery.min.js", // Set of functions designed to create nearly perfect timers that do not drift, // Expected currect time when timeout fires, // Adjusts the timeout to account for any drift since last timeout, // The drift (ms) (positive for overshooting) comparing the expected time to the current time, // Set the next expected currect time when timeout fires, // Clear & delete a timer by ID reference, // Preventing errors when trying to clear a timer that no longer exists, https://codepen.io/shivabhusal/pen/abvmgaV, https://www.growthsnippets.com/30-second-countdown-timer-javascript/. The following shows the complete HTML page: In the index.html file, you place a link to the style.css file in the section and the countdown.js and app.js files in the section. }.