function getCSS()
{
datetoday = new Date();
timenow=datetoday.getTime();
datetoday.setTime(timenow);
thehour = datetoday.getHours();

if (thehour > 20)
display = "css/lay-out-night.css";
else if (thehour < 7)
display = "css/lay-out-night.css";
else
display = "css/lay-out-day.css";

var css = '<';  css+='link rel="stylesheet" href=' + display + ' \/';  css+='>';

document.write(css);
}