December 13, 2022

How to Extract Decimal Number in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to extract decimal number in javascript. A decimal number is one that has a decimal point separating the whole number portion from the fraction portion. For a newbie developer, it can be a bit tricky to extract decimal number.

There are numerous ways to extract decimal number. We are going to use one of the easiest solutions which involve the usage of the match() method. The match() methods matches a string against a regular expression. If the match is found, it returns an array of matches, otherwise returns null.

In the following example, we have one global variable and upon click of a button, we will extract decimal number and display the result on the screen. Please have a look over the code example and the steps given below.

HTML & CSS

We have 3 elements in the HTML file (div, button, and h1). The div element is just a wrapper for the rest of the elements.
The innerText for the button element is “Check” and for the h1 element, it is “Result”.

We have done some basic styling using CSS and added the link to our style.css stylesheet inside the head element.
We have also included our javascript file script.js with a script tag at the bottom.

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <link rel="stylesheet" href="style.css">
  <title>Document</title>
</head>

<body>

  <div class="container">    
    <button>Get</button>
    <h1>Result</h1>
  </div>

  <script src="script.js"></script>
</body>

</html>

.container {        
    text-align: center;
}

button {
  margin-top: 10px;
  padding: 10px 20px;
}

Javascript

We have selected the button element and h1 element using the document.querySelector() method and stored them in btnGet and output variables respectively.
We have attached a click event listener to the button element.
We have a global variable myVar which holds a string as its value.

In the event handler function, we have pattern variable which holds a regex pattern to match a decimal number.
We are using match() method to extract decimal numbers from myVar. If there is a match, we will get an array of decimal numbers. If not, then we will get null. We will store the returned value in the result variable.
Depending upon the value of the result variable, we will either display the decimal numbers or just display "None".

We are displaying the result in the h1 element using the innerText property.

let btnGet = document.querySelector("button");
let output = document.querySelector("h1");

let myVar = "abcdd5.102dfaerrt4.6daagg";

btnGet.addEventListener("click", () => { 

  let pattern = /\d+(\.\d+)?/g;
  let result = myVar.match(pattern);
  output.innerText = result || "None";
  
});

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