function setImage()
{

var el = document.getElementById('1488');
var defaultimageurl = 'day.jpg';
var nightimageurl = 'night.jpg';
var currentTime = new Date();
var hour = currentTime.getHours();

if (hour >= 7 && hour < 21) 
{
el.setAttribute('src',defaultimageurl);
//alert("day");
}
else
	if (hour >= 21 || hour < 7)
{
el.setAttribute('src',nightimageurl);
//alert("night");
}
}
window.onload = setImage;