bmi.js

var age=document.getElementById("age");
var height=document.getElementById("height");
var weight=document.getElementById("weight");
var male=document.getElementById("m");
var female=document.getElementById("f");
var form=document.getElementById("form");

function validateForm() {
    if(age.value == ''|| height.value == ''|| weight.value == ''||(male.checked==false && female.checked==false)) {
        alert("All fields are required");
        document.getElementById("submit").removeEventListener("click",countBmi);
    }
    else {
        countBmi();
    }
}
document.getElementById("submit").addEventListener("click",validateForm);
function countBmi() {
    var p = [age.value,height.value,weight.value];
    if(male.checked) {
        p.push("male");
    }
    else if(female.checked) {
        p.push("female");
    }
    form.reset();
    var bmi = Number(p[2])/(Number(p[1])/100*Number(p[1])/100);
    var result = '';
    if(bmi<18.5)
    {
        result = 'Underweight';
    }
    else if(18.5<=bmi &&bmi<=24.9)
    {
        result='Healthy';
    }
    else if(25<=bmi && bmi <=29.9)
    {
        result='Overweight';
    }
    else if(30<=bmi&&bmi<=34.9)
    {
        result='Obese';
    }
    else if(35<=bmi)
    {
        result='Extremely obese';
    }
    var h1 = document.createElement("h1");
    var h2 = document.createElement("h2");
    var t = document.createTextNode(result);
    var b = document.createTextNode("BMI: ");
    var r = document.createTextNode(parseFloat(bmi).toFixed(2));
    h1.appendChild(t);
    h2.appendChild(b);
    h2.appendChild(r);
    document.body.appendChild(h1);
    document.body.appendChild(h2);
    document.getElementById("submit").removeEventListener("click",countBmi);
    document.getElementById("submit").removeEventListener("click",validateForm);

}
document.getElementById("submit").addEventListener("click",countBmi);