queue.html

<html>
  <head>
    <title>Queue in JavaScript</title>
    <script>
      let queue = [];
      let currentSize = queue.length;
      let maxSize = 5;

      function enqueue(newVal) {
        if (currentSize >= maxSize) {
          alert("Queue is already full");
        } else {
          queue[currentSize] = newVal;
          currentSize++;
        }
      }

      function display() {
        console.warn(queue);
      }
      function dequeue() {
        if (currentSize > 0) {
          for (let i = 0; i < queue.length; i++) {
            queue[i] = queue[i + 1];
          }
          currentSize--;
          queue.length = currentSize;
        } else {
          alert("queue is already empty");
        }
      }

      enqueue(10);
      enqueue(20);
      enqueue(30);

      display();
    </script>
  </head>
  <body>
    <h1>Queue in JavaScript</h1>
  </body>
</html>