AngularJS Program to find the Simple Interest

function simpleInterest(p, t, r) {
  i = (p * t * r) / 100
  return i
}

var p = prompt("Enter principal amount: ");
var t = prompt("Enter time period: ");
var r = prompt("Enter rate of interest: ");
document.write("Simple interest: " + simpleInterest(p, t, r));