krouzek:discoseno

<!DOCTYPE html>
<html>
<style>
body {position: relative}
#seno {position: absolute;left:50px;top:30px}
</style>
<body>
<img id="seno" src="http://adasek.cz/menu/fotky.jpg">
 
</body>
<script>
 
function vykresli(){
 
document.getElementById("seno").style.top = 120*Math.random() +"px"
 
}
 
setInterval(vykresli, 500)
</script>
</html>