When your program contains more than one statement, the statements are executed as if they are a story, from top to bottom. This example program has two statements. The first one asks the user for a number, and the second, which is executed after the first, shows the square of that number.
let theNumber = Number(prompt(“Pick a number”));
console.log(“Your number is the square root of ” + theNumber * theNumber);
The function Number converts a value to a number. We need that conversion because the result of prompt is a string value, and we want a number. There are similar functions called String and Boolean that convert values to those types.
Here is the rather trivial schematic representation of straight-line control flow:
No Starch Press; 3rd edition.