[monolithed]

Примерно так:

<div id="div"></div>

<script type="text/javascript">
window.onload = function(){
    var array = ['a', 'b', 'c', 'd', 'e', 6, 7, 8, 9, 10];
    document.onmousemove = function(){
         return function(){
               document.getElementById('div').innerHTML = array[Math.floor(Math.random() * array.length)];
         };
    }();
};
</script>