function showBox(e){
  if(!document.all) document.body.setStyle({overflow:'hidden'});
  $('overlay').show();
  center(e);
  return false;
}
function hideBox(e){
  if(!document.all) document.body.setStyle({overflow:'visible'});
  $(e).hide();
  $('overlay').hide();
  return false;
}

function center(element, nodisplay){
  try{
    element = $(element);
  }catch(e){
    return;
  }
  var my_width  = 0;
  var my_height = 0;
  if(typeof(window.innerWidth ) == 'number' ) {
    my_width  = window.innerWidth;
    my_height = window.innerHeight;
  } else if(document.documentElement && (document.documentElement.clientWidth || document.documentElement.clientHeight)){
    my_width  = document.documentElement.clientWidth;
    my_height = document.documentElement.clientHeight;
  } else if (document.body && (document.body.clientWidth || document.body.clientHeight)) {
    my_width  = document.body.clientWidth;
    my_height = document.body.clientHeight;
  }
  my_width = '850'; // only as wide as the page (not the browser) is...

  element.style.position = 'absolute';
  element.style.zIndex   = 99;
  var scrollY = 0;
  if(document.documentElement && document.documentElement.scrollTop) {
    scrollY = document.documentElement.scrollTop;
  } else if(document.body && document.body.scrollTop) {
    scrollY = document.body.scrollTop;
  } else if(window.pageYOffset) {
    scrollY = window.pageYOffset;
  } else if(window.scrollY) {
    scrollY = window.scrollY;
  }
  var elementDimensions = Element.getDimensions(element);
  var setX = (my_width - elementDimensions.width) / 2;
  var setY = (my_height - elementDimensions.height) / 2 + scrollY;
  setX = (setX < 0) ? 0 : setX;
  setY = (setY < 0) ? 0 : setY;
  element.style.left = setX + "px";
  element.style.top  = setY + "px";
  if (!nodisplay) {
    element.style.display  = 'block';
  }
}