Javascript xmlhttp获取对nodejs服务器的请求什么都不返回

Question

Before I begin I'd like to tell all of you that I made a lot of searching for solution of this problem on my own.

Here is my nodejs server:

var http = require('http');
http.createServer(function (req, res) {
    console.log("Recived request url " + req.url);
    var sname = req.url.search("name");
    if(sname != -1){
        sname = sname + "name".length + 1;
        var from = sname;
        while(req.url[sname] != '?' && sname<req.url.length){
            sname++;
        }
        var name = req.url.substring(from,sname);
        console.log("Returning parameter of name - " + name);
        res.writeHead(200, {'Content-Type': 'text/plain'});
        res.end(name+'\n');
    }
    else{
        res.writeHead(200, {'Content-Type': 'text/plain'});
        res.end('Error - ask about name\n');
    }

}).listen(1337, '127.0.0.1');
console.log('Server running at http://127.0.0.1:1337/');

It listens on port 1337 and if request url is correct it returns some string.

Here is my javascript code asking nodejs for answer.

function httpGet(theUrl){
    var xmlHttp = null;
    xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", theUrl, true );
    xmlHttp.send( null );
    return xmlHttp.responseText;
}

var url = httpGet("http://127.0.0.1:1337/?name=Mateusz");

setTimeout(function(){
    document.getElementById("actualnewsspace").innerHTML=url;
    var xurl = httpGet("http://127.0.0.1:1337/?"+url);
},5000)

returned xmlHttp.responseText is blank. Why? That's my question.

That's what my nodejs server has to say in this matter

Recived request url /?name=Mateusz
Returning parameter of name - Mateusz
Recived request url /?

If I curl my server it returns mi proper value.

Answer 1

xmlHttp.responseText hasn't been populated when you return it. Ajax is Asynchronous .

See Using XMLHttpRequest and bind an event handler to listen for when the HTTP response has arrived and process the data in that.