In computer or laptop music or sound files are stored in digital form. Sound card is the the device that is used to convert the digital form of music into analog to produce the signal that is compatible with speaker or microphone.
If the speakers are not working on the laptop, means there is no sound produced on speakers. It means that sound card is not working properly.
To avoid fatal errors, it is advised to apply the <u>"use strict"</u> statement locally only to functions that are created rather than globally as the first line of the script file.
