function showIndex(req,res){
var pagePath = __dirname+'/'+'dns-lookup.html';
var html = fs.readFileSync(pagePath);
res.end(html);
}

function lookup(req,res){
var postData = '';
req.on('data',function(data){
postData+=data;
});
req.on('end',function(data){
var json = qs.parse(postData);
var hostname = json.host;
var rrtype = json.rrtype;
dns.resolve(hostname,rrtype,function(err,adresses){
if(err){
res.end(JSON.stringify({errcode:1,ips:[]}));
}
res.end(JSON.stringify({errcode:0,ips:adresses}));
});

});
}

http.createServer(function(req,res){
var pathname = url.parse(req.url).pathname;
req.setEncoding("utf8");
res.writeHead(200,{'Content-Type':'text/html'});
router(req,pathname);
}).listen(3000,'127.0.0.1');