queue.html

<!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>
    <script>
        let queue = [];
        let currentSize = queue.length;
        let maxsize = 5;

        function enqueue(newval){
            if (currentSize<maxsize) {
                queue[currentSize]=newval;
                currentSize++;
            }else{
                console.log('queue is already is full');
            }
        }
        function dqueue() {
            if (currentSize>0) {
                for (let i  = 0; i < maxsize; i++) {
                queue[i]=queue[i+1];
            }
            currentSize--
            queue.length =currentSize
            }
            else{
                console.log('queue is already empty');
            }
        }

        function display(){
            console.log(queue)
        }
        enqueue(30)
        enqueue(31)
        enqueue(32)
        enqueue(33)
        enqueue(34)
        dqueue()
        display()
    </script>
</body>
</html>