function AbreJanela(url, altura, largura, top, left){
    window.open(url, altura, 'toolbar=no, location=no, directories=no, status=no, menubar=no, scrollbars=yes, resizable=no, menubar=no, top='+top+', left='+left+', width='+largura+', height='+altura);
}

function ajax(URL)
{		
	if (window.XMLHttpRequest) //firefox, mozilla, opera
		OBJ = new XMLHttpRequest();
	else if (window.ActiveXObject) //ie
		OBJ = new ActiveXObject("Microsoft.XMLHTTP");
	else
		OBJ = false;
						
	OBJ.open('GET', URL, false);
	OBJ.send(null);	
	
	if (OBJ.readyState == 4)
		return (OBJ.responseText);
	else
		return (OBJ);								
}

function informativo()
{
	var vEmail = document.getElementById('txtEmail').value;
	
	if (vEmail == '' || vEmail == null ||)
	{
		alert('Preencha corretamente o campo');
		document.getElementById('txtEmail').focus();
		return false;
	}
	
	resultado = ajax('informativo.php?email='+ vEmail);
	alert(resultado);
}