function createObject()
{
	var request_type;
	var browser = navigator.appName;
	if(browser == "Microsoft Internet Explorer")
	{
		request_type = new ActiveXObject("Microsoft.XMLHTTP");
	}
	else
	{
		request_type = new XMLHttpRequest();
	}
	return request_type;
}

var http = createObject();
var nocache = 0;
function insert()
{
	var Email= document.getElementById('Email').value;
	nocache = Math.random();
	http.open('get', 'newsletter.php?Email='+Email+'&nocache = '+nocache);
	http.onreadystatechange = insertReply;
	http.send(null);
}

function insertReply()
{
	if(http.readyState == 4)
	{
		var response = http.responseText;
		alert(response);
		document.getElementById('Email').value = "Enter your email";
	}
}