calculator.html

<html>
<body>
<script>

// program to create a simple calculator using the if...else...if in JavaScript.
// take the operator from the user through prompt box in JavaScript.
const operator = prompt('Enter operator to perform the calculation ( either +, -, * or / ): ');

// accept the number from the user through prompt box
const number1 = parseFloat(prompt ('Enter the first number: '));
const number2 = parseFloat(prompt ('Enter the second number: '));

let result; // declaration of the variable.

// use if, elseif and else keyword to define the calculator condition in JavaScript.
if (operator == '+') { // use + (addition) operator to add two numbers
    result = number1 + number2;
}
else if (operator == '-') { // use -  (subtraction) operator to subtract two numbers
    result = number1 - number2;
}
else if (operator == '*') { // use * (multiplication) operator to multiply two numbers
    result = number1 * number2;
}
else {
    result = number1 / number2; // use / (division) operator to divide two numbers
}

// display the result of the Calculator
window.alert(" Result is" + result);
</script>
<body>
</html>

 