gistfile1.js

function moveIt(checkbox) {
var pos = checkbox.value,
    moz = document.getElementById('moz'),
    moz1 = document.getElementById('moz1'),
    moz2 = document.getElementById('moz2'),
    moz3 = document.getElementById('moz3');

switch (pos) {
  case "nw" :
    moz.style.visibility = (checkbox.checked === true) ? "visible" : "hidden";
    break;
  case "ne" :
    moz1.style.visibility = (checkbox.checked === true) ? "visible" : "hidden";
    break;
  case "se" :
    moz2.style.visibility = (checkbox.checked === true) ? "visible" : "hidden";
    break;
  case "sw" :
    moz3.style.visibility = (checkbox.checked === true) ? "visible" : "hidden";
    break;
  default:
    alert('not possible');
  }
}