function ventana(URL)
	{
	var leftpos = (screen.width / 2) - 235;
	window.open(URL,'','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,width=470,height=338,left=' + leftpos + ',top=140')
	}

function ventanav(URL)
	{
	var leftpos = (screen.width / 2) - 160;
	window.open(URL,'','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,width=320,height=488,left=' + leftpos + ',top=140')
	}

function ventanap(URL)
	{
	var leftpos = (screen.width / 2) - 235;
	window.open(URL,'','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,width=470,height=335,left=' + leftpos + ',top=140')
	}
	
function ventanaisee(URL)
	{
	var leftpos = (screen.width / 2) - 260;
	window.open(URL,'','toolbar=0,location=0,directories=0,status=0,menubar=0,scrollbars=0,resizable=0,width=520,height=385,left=' + leftpos + ',top=140')
	}