Why wouldn’t the result display in the browser? – Blancer.com Tutorials and projects

Using alert() in the switch statement works but why wouldn’t it display the result in the browser using the below code?

JS file:

do {
        let playerMove = prompt('Please enter your move', 'e.g rock, paper or scissors');
        let computerMove = ['rock', 'paper', 'scissors'];
        
        switch (playerMove){
            case 'rock':                
                document.querySelector('p').innerHTML= computerMove[Math.floor(Math.random()*3)] + ' vs  your rock';
                break;
            case 'paper':
                document.querySelector('p').innerHTML= computerMove[Math.floor(Math.random()*3)] + ' vs your paper';
                break;
            case 'scissors':        
                document.querySelector('p').innerHTML= computerMove[Math.floor(Math.random()*3)] + ' vs your scissors';
                break;
            default:
                document.querySelector('p').innerHTML= 'You need to learn how to play Rock, Paper, Scissors';
        }                       
    } while (confirm('Wanna play again?'))

HTML file:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h2>Rock Paper Scissors</h2>
    <p></p>
    <script src ='main.js'></script>
</body>
</html>