error upload file with node.js

app.js

var formidable = require('formidable')
, http = require('http')
, util = require('util');

app.get('/song/add', function(req, res){
 
 res.writeHead(200, {'content-type': 'text/html'});
 res.end(
     '<form action="/song/upload" enctype="multipart/form-data" method="post">'+
     '<input type="text" name="title"><br>'+
     '<input type="file" name="upload" multiple="multiple"><br>'+
     '<input type="submit" value="Upload">'+
     '</form>'
 );
 });
 app.post('/song/upload', function(req, res){
 
 var form = new formidable.IncomingForm();
     form.parse(req, function(err, fields, files) {
       res.writeHead(200, {'content-type': 'text/plain'});
       res.write('received upload:\n\n');
       res.end(util.inspect({fields: fields, files: files}));
     });
     return;
  });
 

Now when I try uploading the file, the browser just keep loading forever.....

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