No se puede agregar Div varias veces

window.onload = function(){
var el = document.createElement('div');
el.appendChild(document.createTextNode('Hi'));
for (var i = 10; i > 0; --i)
document.body.appendChild(el.cloneNode(true)); // cloning is important
};
//http://www.dynamicdrive.com/forums/showthread.php?38076-Can-you-append-the-same-node-multiple-times
Sai Ganesh