ok, fai scrivere da php il valore della var log
codice:
<html>
<head>
<title></title>
<script type="text/javascript">
var strBase="Controllo Username in corso";
var log=0;
var testo=new Array("",".","..","...","... OK","... FALLITO")
var idx=-1
var timer=false

function controlla(){
idx=((idx==3)?((log)?4:5):++idx)
document.getElementById('box').innerHTML=strBase+testo[idx];
if(idx>=4) clearTimeout(timer);
else timer=setTimeout("controlla()",1000);
}
window.onload=controlla
</script>
</head>
<body>
<div id="box"></div>
</body>
</html>
ciao