//
// addLoadEvent()
// Adds event to window.onload without overwriting currently assigned onload functions.
// Function found at Simon Willison's weblog - http://simon.incutio.com/
//
function addLoadEvent(func) {
  var oldonload = window.onload;
  if (typeof window.onload != 'function') {
    window.onload = func;
  } else {
    window.onload = function() {
      if (oldonload) {
        oldonload();
      }      
      func();
    };
  }
}

//
// addUnLoadEvent()
// Adds event to window.onload without overwriting currently assigned onload functions.
// Function found at Simon Willison's weblog - http://simon.incutio.com/
//
function addUnloadEvent(func) {
  var oldonunload = window.onunload;
  if (typeof window.onload != 'function') {
    window.onunload = func;
  } else {
    window.onunload = function() {
      if (oldonunload) {
        oldonunload();
      }
      func();
    };
  }
}