April 26, 2022

How to Check if String Starts with Space in Javascript

By Krishnaa JavaScript Questions 0 Comments

In this tutorial, you will learn how to check if string starts with space in javascript. It is very uncommon to have a space in the beginning of a string since in most of the cases it does not make any sense. Sometimes a leading space in a string may be present by mistake. For a newbie developer, it can be a bit tricky to find if a string starts with a space.

There are numerous ways to check if a string starts with a space. We are going to use one of the easiest solutions which involve the usage of the startsWith() method and ternary (?) operator. The startsWith() method checks whether a given string starts with a specified string or not. The ternary operator is also known as the conditional operator which acts similar to the if-else statement.

In the following example, we have one global variable which holds a string as its value. Upon click of a button, we will check if the string starts with a space 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>Check</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 btnCheck and output variables respectively.
We have a global variable myVar 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 startsWith() method and ternary (?) operator to check if myVar starts with a space.
The startsWith() method will return true if the string starts with a space.
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 output = document.querySelector("h1");

let myVar = "  Time is very precious.";

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

  let result = myVar.startsWith(" ") ? "Yes" : "No";
  output.innerText = result;
  
});

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