What does JavaScript mean?
JavaScript is a programming language used for interactive websites and many other applications. In a browser, for example, it can control forms, navigation, and dynamic content.
AN EXAMPLE IN PRACTICE
Where you might encounter it
When a form is submitted, JavaScript checks the entries and displays a clearly visible response. The final validation and processing also take place on the server.
Further sources
From NetzTurm Decode. Clear explanations with historical context.