[danik.js]

<img src="http://javascript.ru/forum/images/smilies/victory.gif" />
<img src="http://javascript.ru/forum/images/smilies/dance3.gif" />
<script>
var hour = new Date().getHours();
var greeting;
if (hour >= 5 && hour < 12)
    greeting = "Доброе утро";
else if (hour >= 12 && hour < 18)
    greeting = "Добрый день";
else if (hour >= 18 && hour < 24)
    greeting = "Добрый вечер";
else if (hour >= 0 && hour < 5)
    greeting = "Доброй ночи";

var i, image;
for (i = 0; image = document.images[i]; i++) {
    image.title = greeting;
}
</script>