var windowX = (screen.width/2)-(800/2)
var windowY = (screen.height/2)-(600/2)
function finestra(variable,url,nom) {

      variable=window.open(url,nom,"toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=yes,resizable=0,copyhistory=0,width=400,height=320")	   
	variable.focus()
    variable.moveTo(windowX,windowY)
}