Here you go:
Code:
<script type="text/javascript">
var div="page_go";
var _ = function(el) { return document.getElementById(el); };
window.onmousemove = function(e){
if(e.pageY <=2 && e.pageX >= 0){
_(div).style.visibility="visible";
}
}
</script>
<style type="text/css">
* { margin: 0; }
#page_go {
width: 100%;
height: 100px;
text-align: center;
visibility: hidden;
font-family: georgia;
border: 1px solid #404040;
background: #E5E9FF;
}
</style>
<div id="page_go">
<h1>Don't go!!</h1>
</div>