April 26, 2022

How to Check if a Text Field is Empty in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to check if a text field is empty in javascript. In HTML, a text field is created using either input element or textarea element. Input element is suitable for a single line text content and textarea element is suitable for multiline text content. From a developer perspective, it can be a bit tricky to find if a text field is empty.

There are numerous ways to check if a text field is empty. But for the sake of simplicity, we will use length property and trim() method. The length property returns the length of the string. If the string is empty, then it will return 0. The trim() method removes any whitespace at the end and beginning of a string.

In the following example, we have one text field where we will enter some random text. Upon click of a button, we will check if the text field is empty and display the result on the screen. Please have a look over the code example and the steps given below.

HTML & CSS

We have 4 elements in the HTML file (div, input, 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">    
    <input type="text" />
    <button>Check</button>
    <h1>Result</h1>
  </div>

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

</html>

.container {        
  text-align: center;
}

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

input {
display: block;
padding: 5px 10px;
margin: auto;
}

Javascript

We have selected the button element, input element, and h1 element using the document.querySelector() method and stored them in btnCheck, inputEl, and output variables respectively.
We have attached a click event listener to the button element.
In the event handler function, we are getting value from the text field and storing it in the value variable.
We are using the trim() method to get rid of trailing and leading whitespaces. Then, we are getting the length of the string using length property and checking if it is equal to 0. If the length is 0, that means the text field is empty.
Depending upon the result of the check, we will assign “Yes” or “No” to the result variable.
We are displaying the result in the h1 element using the innerText property.

let btnCheck = document.querySelector("button");
let inputEl = document.querySelector("input");
let output = document.querySelector("h1");

btnCheck.addEventListener("click", () => {
  let value = inputEl.value;
  let result = value.trim().length == 0 ? "Yes" : "No";
  output.innerText = result;
});

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