function GetXMLHttp() {
	var xmlHttp;
		try { 
			xmlHttp = new ActiveXObject("Msxml2.XMLHTTP"); 
		} catch (e) { 
			try { 
				xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); 
			} catch (E) { 
				xmlHttp = false; 
			} 
		} 
		
		if  (!xmlHttp && typeof  XMLHttpRequest != 'undefined' ) { 
			try  { 
				xmlHttp = new  XMLHttpRequest(); 
			} catch  (e) { 
				xmlHttp = false ; 
			} 
		} 
//alert( GetXMLHttp);
	return xmlHttp;
}
var xmlRequest = GetXMLHttp();			



function validarDados(campo, valor,referencia,info) {
	var ajax = GetXMLHttp();
		var url = "vwajax.php?campo="+campo+"&valor="+valor+"&referencia="+referencia+"&info="+info;
        ajax.open("get", url, true);
		ajax.setRequestHeader('Content-Type','text/html');
		ajax.setRequestHeader('encoding','utf-8');// ISO-8859-1
		
        ajax.onreadystatechange = function() {
			 
                /*if(ajax.readyState == 1) { 
                        document.getElementById('campo_' + campo + '').innerHTML = '<font color="Blue">Carregando...</font>';
						
                }*/
                if(ajax.readyState == 4 && ajax.status == 200) {  
						
                        var resposta = ajax.responseText;
                        document.getElementById('campo_'+ campo +'').innerHTML = resposta;
                }
        }
        ajax.send(null);
}