function lanzaValidaMercado(url){
	if (window.XMLHttpRequest) { // Non-IE browsers
		reqChannel = new XMLHttpRequest();
		reqChannel.onreadystatechange = processRespuesta; 
		try {
			reqChannel.open("GET", url, true);
		}
		catch (e) {
			alert(e);
		}
		reqChannel.send(null);
	}
	else if (window.ActiveXObject) { // IE
		reqChannel = new ActiveXObject("Microsoft.XMLHTTP");
		if (reqChannel) {
			reqChannel.onreadystatechange = processRespuesta; 
			reqChannel.open("GET", url, true);
			reqChannel.send();
		}
	}
}

function processRespuesta() {
	if (reqChannel.readyState == 4) { // Complete
		if (reqChannel.status == 200) { // OK response
			txt = reqChannel.responseText;

			if(txt == "OK")
				document.body.style.display="";
			else
				document.location = txt;
		}
		else {
			alert("Problem: " + reqChannel.statusText);
		}
	}
}