var animals = ["aligator", "bat", "cow"];
var good = document.getElementById("good");
for (var i = 0; i < animals.length; i++) {
  var animal = animals[i];
  var input = document.createElement("input");
  input.type = "button";
  input.value = animal;
  input.style.marginLeft = "5px";
  input.onclick = (function(animal) {return function() {alert(animal);};})(animal);
  good.appendChild(input);
}