Cross-domain jQuery.getJSON from a Node.JS (using express) server does not work in Internet Explorer

Question

This is an annoying problem, and I don\'t suppose that it\'s only IE that has this problem. Basically I have a Node.js server, from which I am making cross-domain calls to g

Answer 1

The following code shows how to handle the GET request (using express) and how to wrap the JSON response using the callback given:

app.get('/foo', function(req, res){ 
  res.header('Content-Type', 'application/json');
  res.header('Charset', 'utf-8') 
  res.send(req.query.callback + '({"something": "rather", "more": "pork", "tua": "tara"});'); 
});

Answer 2

Say we have two servers, myServer.com and crossDomainServer.com, both of which we control.

Assuming we want a client of myServer.com to pull some data from crossDomainServer.com, first that client needs to make a JSONP request to crossDomainServer.com:

// client-side JS from myServer.com
// script tag gets around cross-domain security issues
var script = document.createElement('script');
script.src = 'http://crossDomainServer.com/getJSONPResponse';  
document.body.appendChild(script); // triggers a GET request        

On the cross-domain server we need to handle this GET request:

// in the express app for crossDomainServer.com
app.get('/getJSONPResponse', function(req, res) {
  res.writeHead(200, {'Content-Type': 'application/javascript'});
  res.end("__parseJSONPResponse(" + JSON.stringify('some data') + ");");  
});    

Then in our client-side JS we need a global function to parse the JSONP response:

// gets called when cross-domain server responds
function __parseJSONPResponse(data) {
  // now you have access to your data 
}

Works well across a wide variety of browsers, IE 6 included.