function clean_field(selected_field)
{
	if(selected_field.defaultValue==selected_field.value)
	{
		selected_field.value="";
	}
}

function reset_field(selected_field)
{
	if(selected_field.value=="")
	{
		selected_field.value=selected_field.defaultValue;
	}
}
function CheckSearchForm () {
	var errorMsg = "";
	if (document.siteSearch.search.value==""){
		errorMsg += "\nCerca nel sito \t [Inserire almeno una parola per effettuare la ricerca]";
	}
	if (errorMsg != ""){
		msg = "____________________________________________________________________\n\n";
		msg += "La vostra ricerca non puņ essere effettuata.\n";
		msg += "Siete pregati di controllare i dati e ripetere l'operazione.\n";
		msg += "____________________________________________________________________\n\n";
		msg += "Il seguente campo deve essere controllato:\n";
		
		errorMsg += alert(msg + errorMsg + "\n\n");
		return false;
	}	
	return true;
}
<!--
function MM_reloadPage(init) {  //reloads the window if Nav4 resized
  if (init==true) with (navigator) {if ((appName=="Netscape")&&(parseInt(appVersion)==4)) {
    document.MM_pgW=innerWidth; document.MM_pgH=innerHeight; onresize=MM_reloadPage; }}
  else if (innerWidth!=document.MM_pgW || innerHeight!=document.MM_pgH) location.reload();
}
MM_reloadPage(true);
//-->


function hideBox(id)
{
	document.getElementById(id).style.visibility = "hidden";
}
function showBox(id)
{
	document.getElementById(id).style.visibility = "visible";
}

/*Swap image*/
function swapImage(source, name)
{
	 var obj = document.images[name];
	 var newImg = new Image();
	 newImg.src = source;
	 obj.src = newImg.src;	  
}

function DropDownController() {};

DropDownController.LAYERPREFIX = "drp";
DropDownController.timerHide = document.getElementById("___");

DropDownController.showMenu = function (id)
{
	clearTimeout(DropDownController.timerHide);
	DropDownController.executeHideMenus();
	DropDownController.setMenuLayerVisibility(id, true);
}

DropDownController.hideMenus = function()
{
	DropDownController.timerHide = setTimeout("DropDownController.executeHideMenus()", 500);
}

DropDownController.executeHideMenus = function()
{
	divlist = document.getElementsByTagName("div");
		
	for (var i=0; i<divlist.length; i++)
	{		
		if (divlist[i].id!=null)
		{	
			if ( divlist[i].id.length>=DropDownController.LAYERPREFIX.length &&
				divlist[i].id.substring( 0, DropDownController.LAYERPREFIX.length )== DropDownController.LAYERPREFIX )
					DropDownController.setMenuLayerVisibility(divlist[i].id, false);
		}

	}
}

DropDownController.setMenuLayerVisibility = function(menuID, isVisible)
{
	if (isVisible)
		document.getElementById(menuID).style.display = "block";
	else
		document.getElementById(menuID).style.display = "none";
}