function GetXmlHttpObject()
{
	var xmlHttp=null;
	try
	{
		// Firefox, Opera 8.0+, Safari
		xmlHttp=new XMLHttpRequest();
	}
	catch (e)
	{
		// Internet Explorer
		try
		{
			xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
		}
		catch (e)
		{
			xmlHttp=new ActiveXObject("Microsoft.XMLHTTP");
		}
	}
	return xmlHttp;
}

function stateChanged() 
{ 
	if (xmlHttp.readyState==4)
	{ 
		risposta = xmlHttp.responseText;
		
		if (risposta=='OK')
		{
			document.getElementById(id_form).submit();
		}
		else
		{
			alert(alert_codice_errato);
		}
	}
}

function inviaForm()
{
	xmlHttp=GetXmlHttpObject();
	if (xmlHttp==null)
	{
		alert (alert_no_ajax);
		return;
	} 
	var url = pagina_sendmail+'?strCAPTCHA='+document.getElementById('strCAPTCHA').value;
	url = url + '&rnd='+Math.random();
	
	xmlHttp.onreadystatechange=stateChanged;
	xmlHttp.open("GET",url,true);
	xmlHttp.send(null);
}