JS (c)

Window.prompt and Document.writeln functions

Prompt is a built-in function of the system-provided window object that provides an input box on a Web page and returns a response

The Writeln function is to write an HTML expression or JS code to the document, which you can output to the browser.

Note: In logical operation 0, "", false, null, undefined, Nan all indicate false

Logical OR | | : Returns the first value (or object) that is not false, or returns the last value (all values are false)

The return value is also not necessarily a Boolean value, or it can be an object.

The switch statement can be any data type supported by JS (except for arrays and objects).

The data type behind the case can be arbitrarily mixed with

JS (c)