Skip to main content

Creating a Simple Countdown Timer Using JavaScript II...Using getElementById() Method

Using getElementById(id) Method

Speaking of yesterday’s post, it had the following problems:

1. It could not easily be embedded into an existing page.
2. It could not be placed wherever we wanted it to be nor it could be aligned or styled easily.
3. Rather than updating the same number to countdown it showed a series of numbers as countdown proceeded.

Well all these problems can easily be solved by one of JavaScript’s powerful method getElementById(). This is documents’s method which can be used to access HTML entities within JavaScript with the help of their IDs (which is unique).

For example we can access the HTML entity and its values etc. with the ID one as:


The HTML object may be defined like below:

<p id="one">some text</p>

You get!

OK, how can this be used to solve our problems, let’s see.

As we know, the HTML entities such as <p>,<div>, <span> etc. can be placed anywhere very easily. They can also be styled and aligned perfectly. So if we could print the timer in one of these, it’d be the most efficient technique. How? Using getElementById().

The body of tags such as <p>, <div> or <span> can be accessed via JavaScript as:


e.g.: If we execute the following code:


it’d be same as having the following HTML tag:

<p id="one">hello!!"</p>

This way two of our problems have been solved. What about the third one? It too has been solved, if you look closely.

For example when you write:


And then:


The <p> would be displayed as having the text “Second”.

OK, below is the completed code:

  <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

  <title>JavaScript Countdown Timer</title>
  <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
  <script language="JavaScript" type="text/JavaScript">

  //to store timeout ID
  var tID;
  function tickTimer(t,id)
    //if time is in range
    //stop the timeout event

      document.getElementById(id).innerHTML="Time Out!!";

  //function to stop the timeout event
  function killTimer(id)

  <!--style the ID -->

  #timer {
    background: #000;
    color: #fff;
    font-size: 20px;
  <!--pass the id to timer has to attached to -->
  <body onLoad="tickTimer(9,'timer')" onUnload="killTimer(tID)">

  <p>Timer: <span id="timer"></span></p>

It depends on what you intend regarding which tag you should use to place to timer. If you want it to be inline with some text use <span>. <p> would make it to be in a different paragraph.

So in this post we saw a very powerful method getElementById() which can be used to access HTML objects and manipulate them. Check back for more!

Previous Posts:

Popular posts from this blog

Fix For Toshiba Satellite "RTC Battery is Low" Error (with Pictures)

RTC Battery is Low Error on a Toshiba Satellite laptop "RTC Battery is Low..." An error message flashing while you try to boot your laptop is enough to panic many people. But worry not! "RTC Battery" stands for Real-Time Clock battery which almost all laptops and PCs have on their motherboard to power the clock and sometimes to also keep the CMOS settings from getting erased while the system is switched off.  It is not uncommon for these batteries to last for years before requiring a replacement as the clock consumes very less power. And contrary to what some people tell you - they are not rechargeable or getting charged while your computer or laptop is running. In this article, we'll learn everything about RTC batteries and how to fix the error on your Toshiba Satellite laptop. What is an RTC Battery? RTC or CMOS batteries are small coin-shaped lithium batteries with a 3-volts output. Most laptops use

The Best Way(s) to Comment out PHP/HTML Code

PHP supports various styles of comments. Please check the following example: <?php // Single line comment code (); # Single line Comment code2 (); /* Multi Line comment code(); The code inside doesn't run */ // /* This doesn NOT start a multi-line comment block /* Multi line comment block The following line still ends the multi-line comment block //*/ The " # " comment style, though, is rarely used. Do note, in the example, that anything (even a multi-block comment /* ) after a " // " or " # " is a comment, and /* */ around any single-line comment overrides it. This information will come in handy when we learn about some neat tricks next. Comment out PHP Code Blocks Check the following code <?php //* Toggle line if ( 1 ) {      // } else {      // } //*/ //* Toggle line if ( 2 ) {      // } else {      // } //*/ Now see how easy it is to toggle a part of PHP code by just removing or adding a single " / " from th

How to Create an HTML Form Linked with MySQL Database in PHP

If you're looking for example code and detailed discussion on how to create an HTML form that stores data in a MySQL database using PHP then this post might be what you're looking for. I assume that you're familiar with basic HTML, CSS, PHP coding, and  MySQL. I am going to divide this small project into two parts: The HTML form itself that takes input from the user and the PHP script that saves it into the database A table that displays the user-added data that has been saved in the database. We'll be dealing with the first part in this tutorial. Again I'd like to break this problem into a few parts so that it's easier for you to understand and probably gives you an insight into how breaking up a problem into smaller chunks can help make things clearer in your mind. Let's think about it, there is an HTML form (that is HTML code), then there is the PHP code that deals with the user-input data, and the MySQL database itself. For this tutorial, we'll b