title: Pass data from Python (flask framework) to javascript
body: <p>I try to pass data (exactly a path or a url) from flask to a javascript. But it don't recognize my variable.
  On the server side: it upload a file, process this file and then create and save many images. When I try to pass the path to a javascript file which use three.js library it doesn't. </p>
  
  <pre><code>@app.route('/upload', methods=['POST'])
  def upload_file():
      print('coucou')
      if request.method == 'POST':
          file = request.files['file']
          print(file)
          # if file and allowed_file(file.filename):
          filename = secure_filename(file.filename)
          print(filename)
          file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
          path = UPLOAD_FOLDER + filename
          fits_reader = FitsReader.FitsReader()
          fits_reader.open_file(path)
          cube_faces = ['/home/morban/essaiserver/cube3D/CubeX.PNG', '/home/morban/essaiserver/cube3D/CubeY.PNG', '/home/morban/essaiserver/cube3D/CubeZ.PNG']
      return render_template('index.html', cube_faces=cube_faces)
  
  
  
  
  for (var i = 0; i &lt; 3; i++) {
          switch (i) {
              case 0:
                  texture[i] = new THREE.ImageUtils.loadTexture('{{ cube_faces[0] }}');
                  console.log('{{ cube_faces[0] }}')
                  break;
              case 1:
                  texture[i] = new THREE.ImageUtils.loadTexture('{{ cube_faces[1] }}');
                  break;
              case 2:
                  texture[i] = new THREE.ImageUtils.loadTexture('{{ cube_faces[2] }}');
                  break;
              }
  </code></pre>