window.onload = () => {
let button = document.querySelector(“#btn”);

// Function for calculating BMI
button.addEventListener(“click”, calculateBMI);
};

function calculateBMI() {

/* Getting input from user into height variable.
Input is string so typecasting is necessary. */
let height = parseInt(document
.querySelector(“#height”).value);

/* Getting input from user into weight variable.
Input is string so typecasting is necessary.*/
let weight = parseInt(document
.querySelector(“#weight”).value);

let result = document.querySelector(“#result”);

// Checking the user providing a proper
// value or not
if (height === “” || isNaN(height))
result.innerHTML = “Provide a valid Height!”;

else if (weight === “” || isNaN(weight))
result.innerHTML = “Provide a valid Weight!”;

// If both input is valid, calculate the bmi
else {

// Fixing upto 2 decimal places
let bmi = (weight / ((height * height)
/ 10000)).toFixed(2);

// Dividing as per the bmi conditions
if (bmi < 18.6) result.innerHTML = `Under Weight : ${bmi}`;

else if (bmi >= 18.6 && bmi < 24.9) result.innerHTML = `Normal : ${bmi}`;

else result.innerHTML =
`Over Weight : ${bmi}`;
}
}