script.js

function compute()
{
    var principal = document.getElementById("principal").value;

    if (principal<=0){ // if the input value is not >0
    alert("Enter a positive number");
    document.getElementById("principal").focus();
    }
    else{
    var rate = document.getElementById("rate").value;
    var years = document.getElementById("years").value;

    var interest = principal * years * rate / 100;

    var amount = interest + principal;

    var year = new Date().getFullYear() + parseInt(years);

    document.getElementById("result").innerHTML= "If you deposit <mark>"+principal+"</mark>,\<br\>at an interest rate of <mark>"+rate+"%</mark>\<br\>You will receive an amount of <mark>"+amount+"</mark>,\<br\>in the year <mark>"+year+"</mark>\<br\>";
    }
    

}

function updateRate() //show updated rate when adjust bar
    {

    var principal = document.getElementById("principal").value;
    var rate = document.getElementById("rate").value;
    var years = document.getElementById("years").value;

    var interest = principal * years * rate / 100;

    var year = new Date().getFullYear() + parseInt(years);
    var rateval = document.getElementById("rate").value;
    document.getElementById("rate_val").innerText=rateval +"%";

     
    }