<script language="JavaScript">

function textCounter(field,  maxlimit) {

     if (field.value.length > maxlimit) // if too long...trim it!
     {
          field.value = field.value.substring(0, maxlimit);
     }

}

</script>


<textarea name="comments" rows="5" cols="20" 

onKeyDown="textCounter(this.form.comments,100);" 

onKeyUp="textCounter(this.form.comments,100);"></textarea>

<div align="center"><small>100 characters</small></div>