is_1 = document.getElementById ? true : false;
is_2 = document.all ? true : false;
is_3 = document.layers ? true : false;

function getDOMObject(ObjectId) {
	if (is_1) {
		return document.getElementById(ObjectId);
	}
	else if (is_2) {
		return document.all[ObjectId];
	}
	else if (is_3) {
		return document.layers[ObjectId];
	}
}

var _xmlhttp, _id;

/*@cc_on @*//*@if (@_jscript_version >= 5)
var idAX = ["Msxml2.XMLHTTP.5.0","Msxml2.XMLHTTP.4.0","Msxml2.XMLHTTP.3.0","Msxml2.XMLHTTP","Microsoft.XMLHTTP"];
for(var i=0; !_xmlhttp && i<idAX.length; i++)
{try{ _xmlhttp = new ActiveXObject(idAX[i]);}
catch(ex) { _xmlhttp = false; }
}@end @*/

if (!_xmlhttp && typeof XMLHttpRequest != 'undefined') {
	_xmlhttp = new XMLHttpRequest();
}

function evaluarResultado() {
	if (_xmlhttp.readyState == 1) {
		getDOMObject(_id).innerHTML = "Procesando...";
	}
	else if (_xmlhttp.readyState == 4) {
		if (_xmlhttp.status == 200) {
			getDOMObject(_id).innerHTML = _xmlhttp.responseText;
		}
		else {
			getDOMObject(_id).innerHTML = "Se gener&oacute; un error:\n" + _xmlhttp.statusText;
		}
	}
}

function leerPagina(url, id) {
	if (_xmlhttp.readyState == 4 || _xmlhttp.readyState == 0) {
		_id = id;
		_xmlhttp.open("GET", url, true);
		_xmlhttp.onreadystatechange = evaluarResultado;
		_xmlhttp.send(null);
	}
}