function nuevoAjax(){
	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 listaNegocios(codigo){
  var contenedor;
  contenedor = document.getElementById('contenedor');
  ajax=nuevoAjax();
  ajax.open("GET", "ajax_negocios.php?id="+codigo,true);
  ajax.onreadystatechange=function() {
  if(ajax.readyState == 1){
	contenedor.innerHTML = "<img src='images/loading.gif' width='25' height='25'>";
  }else if(ajax.readyState==4){
	contenedor.innerHTML = ajax.responseText
  }
  }
  ajax.send(null)
}