Validate and add user input number

by isuru_nan

HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="stylesheet" href="src/style.css" />
  </head>
  <body>
    <label for="num">Enter a number</label>
    <input id="userNumber" type="number" name="num" />
    <button id="addButton">Add</button>

    <script>
      addButton.addEventListener("click", addNumber);

      function addNumber() {
        const inputNumber = document.getElementById("userNumber").value.trim();
		
        var total = 0;
        var noOfInputs = 0;
        var largestNumber = 0;
        var smallestNumber = 0;
        
        if (isNaN(inputNumber)) {
          alert('Not a number');
          return;
        }

		while (true) {
			if (inputNumber === -999) {
				break;
			}
			
			noOfInputs++;
			total += inputNumber
			
			if (inputNumber < smallestNumber) {
				smallestNumber = inputNumber;
			}
			if (inputNumber > largestNumber) {
				largestNumber = inputNumber
			}
		}
		
		console.log("Total of the numbers entered: " + total);
		console.log("No of times the user entered a number: " + noOfInputs);
		console.log("The largest number entered: " + largestNumber);
		console.log("The smallest number entered:" + smallestNumber);
      }
    </script>
  </body>
</html>