April 5, 2022

How to Determine the Length of a String in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to determine the length of a string in javascript. The length of a string represents the total number of characters in that string.

There are numerous ways to determine the length of a string. But for the sake of simplicity, we will use length property. The length property returns the length of the string. If the string is empty, then it will return 0.

In the following example, we have one global variable that holds a string. Upon click of a button, we will determine the length of a string and display it 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 “Get” 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 a global variable myString which holds a string as its value.
We have attached a click event listener to the button element.
In the event handler function, we are using the length property to get the length of myString. We are assigning the returned value to the result variable.
We are displaying the result in the h1 element using the innerText property.

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

let myString = "Hello world";

btnGet.addEventListener("click", () => {  
  let result = myString.length;
  output.innerText = result;
});

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