Example of a Code

        function calculateLb() {
            var input = document.getElementById("numberInput");
            var x = parseFloat(input.value);
            if (!isNaN(x) && x > 0) {
              var l = Math.log2(x);
              var result = document.getElementById("result");
              result.innerHTML = "Lb(" + x + ") = " + l.toFixed(4); 
            } 
            else {
              alert("Please enter a valid positive number.");
            }
          }