var pop = null;
function popup(file)
{
	pop = window.open(file, 'Popup', 'width=450,height=550,left=100,top=200,resizable=yes,scrollbars=yes');
	pop.focus();
	if(pop)	{
		return false;
	} else {
		return true;
	}
}

function clearPopup()
{
	if (pop && !pop.closed) pop.close();
}

function init()
{
}

function unloadCallback()
{
  clearPopup();
}

function focusCallback()
{
  clearPopup();
}

window.onload = init;
window.onunload = unloadCallback;
window.onfocus = focusCallback;