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

function resolver(){
	padre = document.getElementById('sel_reg').value;
	ajax=Ajax();
	ajax.open("GET", "out_file.php?campo="+padre);
	ajax.onreadystatechange=function(){
		if (ajax.readyState==4){
			document.getElementById('file').innerHTML = ajax.responseText;
		}
	}
	ajax.send(null);
}