Web 2 MC

<style>   
    textarea{
        font-family:verdana, arial;
        font-size:10px;
        width:300px;
        height: 100px;
    }   
    #preview{
        font-family:verdana, arial;
        font-size:10px;
        width:30px;
        height: 20px;
        border:1px solid #000000;
        background-color:#cccccc;
        color:#8F3E3E;
        overflow:auto;
    }
</style>
<script>
     function showpreview(limite){   
        contenuto_testo=limite-document.getElementById("testo").value.length;   
        if (contenuto_testo<0){
            document.getElementById("testo").innerHTML=document.getElementById("testo").value.substring(0,limite-1);
            document.getElementById("preview").innerHTML=limite-document.getElementById("testo").value.length;
        } else {
            document.getElementById("preview").innerHTML=contenuto_testo;
        }   
    }
</script>
<textarea id="testo" onkeyup="showpreview(255)"></textarea>
<br/>Caratteri rimanenti:<br/><div id="preview"></div>