HTML | <audio> src Attribute The HTML <audio> src attribute is used to specify the URL of the audio files. We should use the Mp3 file for play the audio in the Internet Explorer and Safari Browsers. The source element can be used to add audio files to a webpage to work in all the Browsers.

send_file transfers the contents of a file to the client using the most efficient method available and configured in the Flask settings. It attempts to guess the correct mimetype to use but it can also be explicitly configured. Note that send_file is usually imported directly from flask instead of from flask.