lo ho creato ora, spero vada


<script>
function carica(){
level=document.getElementById('livello')
level.style.visibility='hidden'
}
function fuori(){
level.style.visibility='hidden'
}
function sopra(){
level.style.visibility='visible'
}
function sposta(){
level.style.left=event.clientX
level.style.top=event.clientY
}
</script>

<body onload="carica()">
<div id="livello" style="position:absolute; background-Color:aqua; width:10; height:10;">TESTOOOOO</div>
<p onMouseOver="sopra()" onMouseOut="fuori()" onMouseMove="sposta()">Ciao!</p>