I am having a problem with my Slider

[snippsat]

Here is folder setup.

slider\
|-- app.py
  templates\
    |-- index.html
  static\
    css\
      |-- style.css # can be empty or missing

You have done pip install Flask
In folder:

E:\all_flask\2019\slider
λ ls # or dir in cmd
app.py  static/  templates/

# Check install
E:\all_flask\2019\slider
λ pip install Flask
Requirement already satisfied: Flask in c:\python37\lib\site-packages (1.0.2)
Requirement already satisfied: Werkzeug>=0.14 in c:\python37\lib\site-packages (from Flask) (0.14.1)
Requirement already satisfied: itsdangerous>=0.24 in c:\python37\lib\site-packages (from Flask) (0.24)
Requirement already satisfied: click>=5.1 in c:\python37\lib\site-packages (from Flask) (7.0)
Requirement already satisfied: Jinja2>=2.10 in c:\python37\lib\site-packages (from Flask) (2.10)
Requirement already satisfied: MarkupSafe>=0.23 in c:\python37\lib\site-packages (from Jinja2>=2.10->Flask) (1.0)

# Run app
E:\all_flask\2019\slider
λ python app.py
 * Serving Flask app "app" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 334-187-997
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)

Now you see address http://127.0.0.1:5000/ copy to browser.
How it shall look in browser,see that values are live updated when move slider.