var calque;

function cachepopup ()
{
calque = document.getElementById('popup').style;
calque.visibility = 'hidden';
}

document.images['imgpop'].src='popupdestockage.jpg';
calque = document.getElementById('popup').style;
calque.visibility = 'visible';
calque.top='400px';
calque.left='500px';
//1000 = 1 seconde
window.setTimeout("cachepopup()",5000);