/* function $(id)
  {
    return document.getElementById(id);
  }
  
  function autentica(username,password)
  {
    var url = "./server.php";
    new Ajax(url,callback,{user : username, pass : password});
    return false;
  }
  
  function callback(elements)
  {
    if(elements != 0 && elements[0].id)
    {
      if(document.getElementById('autenticazione') && document.getElementById('data'))
      {
        opacity('data', 80, 0,'300');
        opacity('autenticazione', 80, 0,'300');
        
        setTimeout('body_remove(\'autenticazione\')',999);
        setTimeout('body_remove(\'data\')',999);
        setTimeout('redirect(\''+document.location+'\')',299);
      }
    }
    else
    {
      var autenticazione = document.getElementById('autenticazione');
      autenticazione.innerHTML = '<span id=\'error\' style=\'opacity: 0; filter: alpha(opacity:0);\'>Dati errati, ritenta<span>';
      opacity('error',0,100,999);
      setTimeout('opacity(\'error\',100,0,599)',2999);
    }
  }
  
  
  function opacity(id, opacStart, opacEnd, millisec) 
  {
    //speed for each frame
    var speed = Math.round(millisec / 100);
    var timer = 0;
      
    //determine the direction for the blending, if start and end are the same nothing happens
    if(opacStart > opacEnd) 
    {
      for(i = opacStart; i >= opacEnd; i--) 
      {
        setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
        timer++;
      }
    } 
    else if(opacStart < opacEnd) 
    {
      for(i = opacStart; i <= opacEnd; i++)
      {
        setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
        timer++;
      }
    }
  }

  //change the opacity for different browsers
  function changeOpac(opacity, id) 
  {
    try
    {
      var object = document.getElementById(id).style;
      if(object)
      {
        object.opacity = (opacity / 100);
        object.MozOpacity = (opacity / 100);
        object.KhtmlOpacity = (opacity / 100);
        object.filter = "alpha(opacity=" + opacity + ")";
      }
    }
    catch(e)
    {
      void(0);
    }
  } 
  
  function getOpacity(id)
  {
    try
    {
      var object = document.getElementById(id).style;
      if(object)
      {
        if(object.opacity)
          return object.opacity;
        else if(object.MozOpacity)
          return object.MozOpacity;
        else if(object.KhtmlOpacity)
          return object.KhtmlOpacity;
        else if(object.filter)
          return object.filter;
        else 
          return false;
      }
      else
        return false;
    }
    catch(e)
    {
      void(0);
    }
  }
  
  function body_remove(id)
  {
    try
    {
      if(document.getElementById(id))
      {
        var element = document.getElementById(id);
        document.body.removeChild(element);
      }
    }
    catch(e)
    {
      void(0);
    }
  }
  
  function redirect(url)
  {
    document.location.href = url;
  }*/
  
  
  /* Resetta dei field in un form */
  function formFieldFocusListener(id,valueToReset)
  {
    var obj;
    if(obj = $(id))
    {
      if(obj.value == valueToReset)
      {
        obj.value = '';
      }
    }
  }
  
  /* Resetta dei field in un form */
  function formFieldBlurListener(id,valueToInsert)
  {
    var obj;
    if(obj = $(id))
    {
      if(obj.value == '')
      {
        obj.value = valueToInsert;
      }
    }
  }
  
  
  function showHideOnclickListener(toHide,toShow)
  {
    var obj1;
    var obj2;
    if( (obj1 = $(toHide)) && (obj2 = $(toShow)) )
    {
      obj1.style.display = 'none';
      obj2.style.display = 'block';
    }
    return void(0);
  }
  
  function onMouseListener(id,color,cursor)
  {
    var obj;
    if(obj = $(id))
    {
      obj.style.background = color; 
      obj.style.cursor = cursor;
    }
  }
  
  // Funzione per la visualizzazione del div tutte le categorie
  function createDiv(x,y,w,h,contents)
  {
    if(w == 0)
      w = 'auto';
    else
      w = w+'px';
      
    if(h == 0)
      h = 'auto';
    else
      h = h+'px';
      
    try
    {
      if(div = document.getElementById('brwsr'))
      {
        // recuperiamo la sua opacità
        var opac = getOpacity('brwsr');
        if(opac == 1)
        {
          opacity('brwsr',100,0,1000);
          setTimeout('body_remove(\'brwsr\')',999);
          return;
        }
        else
          return;
      }
      
      var div = document.createElement('div');
      div.style.zIndex = 100;
      div.style.width = w;
      div.style.height = h;
      div.style.position = 'absolute';
      div.style.top = y+'px';
      div.style.left = x+'px';
      div.style.border = '1px solid black';
      div.style.background = 'orange';
      div.setAttribute('id','brwsr');
      document.body.appendChild(div);
      div.innerHTML = contents;
      changeOpac(20,'brwsr');
      opacity('brwsr',20 ,100, 1000);
    }
    catch(e)
    {
      void(0);
    }
  }
  
  
  function ScrollMessage(msg,id,speed,step,show,pos) 
  {
    try
    {
      var newtext = msg.substring(pos,pos+show);
      var div = document.getElementById(id);
      div.innerHTML = newtext;
      pos = pos+step;
      if (pos > msg.length) pos = 0;
      window.setTimeout('ScrollMessage("'+msg+'","'+id+'",'+speed+','+step+','+show+','+pos+')',speed);
    }
    catch(e)
    {
      alert(e);
    }
  }