Is it possible to set a maximum number of characters input ?

<script language=javascript>
   var count = "800";   
   function limiter(){
   var tex = document.theForm.'.$label.'.value;
   var len = tex.length;
   var limit = count-len;
   if(len > count){
          tex = tex.substring(0,count);
         document.theForm.'.$label.'.value =tex;
                      return false;
   }
   document.theForm.limit.value =limit;
}
</script>';
<form....
echo '
<textarea rows="10" name="'.$label.'" cols="60" class="formstyle" maxlength="'.$len.'" onkeyup=limiter()>
'.$entity_row[$i].'</textarea>

<script language=javascript>
document.write("<input type=text name=limit size=4 readonly value="+count+">");
</script>
</form>