access to xmlhttprequest at from origin 'null' has been blocked by cors policy code example

Example 1: javascript access to xmlhttprequest at from origin 'null' has been blocked by cors policy

//Open the HTML file using live server, it will work

Example 2: access to image at from origin

//use crossorigin="anonymous" sttribute in img tag

<img src="https://upload.wikimedia.org/wikipedia/commons/f/f9/Phoenicopterus_ruber_in_S%C3%A3o_Paulo_Zoo.jpg" id="external-flamingo" crossorigin="anonymous">

Example 3: ccess to XMLHttpRequest at 'http://127.0.0.1:5000/ has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

@app.route('your route', methods=['GET'])
def yourMethod(params):
    response = flask.jsonify({'some': 'data'})
    response.headers.add('Access-Control-Allow-Origin', '*')
    return response