Edit in JSFiddle


              
            
          
            
              
                
<html>
<head>
<script type='text/javascript'>


a = new Array();

function unico(){
    
    if(a.length > 100){
        clearInterval(id);
        imprimir();
    }
    else {
        a.push(new Date().getTime());
    }
}

function imprimir(){
    for(var i = 0; i < a.length; i++){
        document.write(i +" = " + a[i] + "<br/>")
    }
    
    for(var i = 0; i < a.length; i++){
        if(a[i] == a[++i]){
            alert('Hay un numero repetido');
        }
        
    }
    
}

function limpiar(){
    
}

</script>
</head>
<body>
<script type='text/javascript'>
id = setInterval(unico, 100);
</script>


</body>
</html>