JavaScript Methods to Increment/Decrement Alphabetical Letters

Last Updated : 20 Jun, 2023

The task is to increment/decrement alphabetic letters using ASCII values with the help of JavaScript.

Approach:

Use charCodeAt() method to return the Unicode of the character at the specified index in a string.
Increment/Decrement the ASCII value depending on the requirement.
Use fromCharCode() method to convert Unicode values into characters.

Example 1: In this example, the character ‘a’ is incremented by clicking on the button.

html

<!DOCTYPE html>
<html lang="en">
 
<head>
    <title>
          Click on the button to 
        increment the letter
      </title>
</head>
 
<body>
    <h1 style="color:green;">
        GeeksforGeeks
    </h1>
 
    <p>
        Click on the button to 
        increment the letter.
    </p>
 
    <button onclick="GFG_Fun()">
        click here
    </button>
 
    <p id="GFG"></p>
 
    <script>
        var down = document.getElementById('GFG');
 
        down.innerHTML = 'a';
 
        function nextCharacter(c) {
            return String.fromCharCode(c.charCodeAt(0) + 1);
        }
 
        function GFG_Fun() {
            let c = down.innerHTML;
            down.innerHTML = nextCharacter(c);
        }
    </script>
</body>
 
</html>

Output:

JavaScript methods to increment/decrement alphabetical letters

Example 2: In this example, the character ‘z’ is decremented by clicking on the button.

html

<!DOCTYPE html>
<html lang="en">
 
<head>
    <title>
        Click on the button to 
        decrement the letter
    </title>
</head>
 
<body>
    <h1 style="color:green;">
        GeeksforGeeks
    </h1>
 
    <p>
        Click on the button to 
        decrement the letter.
    </p>
 
    <button onclick="GFG_Fun()">
        click here
    </button>
 
    <p id="GFG"></p>
 
    <script>
        var down = document.getElementById('GFG');
 
        down.innerHTML = 'z';
 
        function nextCharacter(c) {
            return String.fromCharCode(c.charCodeAt(0) - 1);
        }
 
        function GFG_Fun() {
            let c = down.innerHTML;
            down.innerHTML = nextCharacter(c);
        }
    </script>
</body>
 
</html>