This document provides an introduction to JavaScript concepts like variables, functions, and data types. It uses examples from Project Loon, a Google project that uses high-altitude balloons to provide internet access, to explain how balloons communicate data to ground stations using JavaScript functions. Key concepts covered include defining variables to store data, the different data types in JavaScript, and how functions allow balloons to send and receive data and commands.

1. WTF is JavaScript?
I dunno.
Let’s learn some stuff together.

2. 1. Getting Familiar
2. Variables
3. Functions

3. JavaScript console

4. Math

6. Letters/Characters

9. let’s get weird

18. Booleans

20. let’s get weird

27. 1. Getting Familiar
2. Variables
3. Functions

28. Project Loon
http://www.google.com/loon/

29. How does a balloon and ground control
communicate?!
How can data be stored?

36. Refresher
23 is a Number!
“my name is Robert” is a String of characters!
47.092872635 is a Floating point number!
true and false are Boolean values

37. Variables Exercise
In your JavaScript console, create variables for the
following data points and then call the variable
name in order to make sure you did it correctly.!
altitude in meters (Float)!
latitude/longitude (String)!
# of active connections (Number)!
the Balloon’s name it chose for itself (String)

38. 1. Getting Familiar
2. Variables
3. Functions

39. -Stuart (Balloon #8675309)
“Hooray; I have data! Now what…?”

40. How can data and commands be sent?!
How can data and commands be received?

41. Functions
to the rescue

42. What is a function?
It is dumb.!
Executes the code within it!
Always returns a value!
Can be passed “arguments” with which it can
process information

46. Let’s do something
interesting

49. Why doesn’t this work?

50. Variables defined within a function are
*scoped* within that function. They
are *private* and are inaccessible to
anything outside of the function.

51. We need to be able to *pass* the data to the other
function.
!
This is known as *passing arguments* and, on
the other end, *accepting arguments*

54. Don’t be a jerk. Name
things appropriately.

56. Functions Refresher
Functions are dumb. They don’t know much
about the world unless you tell them.!
Functions can be called by adding () on the end
of the function name.!
Functions are an effective method of grouping
and reusing certain actions that perform a
given…function.

57. Functions Exercise
Write two functions:!
getNearbyBalloonCount() (which is reported
by the balloon and passes the balloon’s name,
as well as how many balloons are near her.)!
logBalloonCount() (received by the ground
station and logs to the console the values that
were passed)