var http_request = false;
var replace_into='';
function makePOSTRequest(url, parameters,area) 
	{
	//alert(parameters);
  	replace_into = area;
  	http_request = false;
  	if (window.XMLHttpRequest) 
		{ // Mozilla, Safari,...
	 	http_request = new XMLHttpRequest();
	 	if (http_request.overrideMimeType) 
			{
			// set type accordingly to anticipated content type
			//http_request.overrideMimeType('text/xml');
			http_request.overrideMimeType('text/html');
	 		}
		} 
 	else if (window.ActiveXObject)  // IE
		{
	 	try 
			{
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
	 		}
		catch (e) 
			{
			try 
				{
			   	http_request = new ActiveXObject("Microsoft.XMLHTTP");
				} 
			catch (e) 
				{
				}
	 		}
  		}
  	if (!http_request) 
		{
	 	alert('Cannot create XMLHTTP instance');
	 	return false;
  		}
  
  http_request.onreadystatechange = alertContents;
  http_request.open('POST', url, false);
  http_request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  http_request.setRequestHeader("Content-length", parameters.length);
  http_request.setRequestHeader("Connection", "close");
  http_request.send(parameters);
}

function alertContents() 
	{
  	if (http_request.readyState == 4) 
		{
	 	if (http_request.status == 200) 
			{
			//alert(http_request.responseText);
			result = http_request.responseText;
			document.getElementById(replace_into).innerHTML = result;            
	 		} 
		else 
			{
			alert('There was a problem with the request.');
	 		}
  		}
	}
   
function signup()
	{
	email = document.getElementById('email_address').value;	
	//alert(email);
	if(email_check(email))
		{
		post = 'email_address=' + email;
		makePOSTRequest('newsletter.php',post,'ubu_left_nav6');	
		}
	}
function email_check(email)
{
	//alert(email);
	var emailchar = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i;
	if (emailchar.test(email)){
		return true
	}
	else
	{
		alert("Please, enter a valid email address.");
		return false;
	}
}