JavaScript Variables and Data Types Worksheet

Question 1

Find a reference that lists all the keywords in the JavaScript programming language.

Java.com

Question 2

True or false: keywords and variable names are NOT case sensitive.

False

Question 3

There are some rules for how you can name variables in JavaScript. What are they?

You should use no spaces and Case sensitivity

Question 4

What is 'camelCase'?

Its where something is in all lowercase and the word starts with a capital letter with no spaces in it

Question 5

What are ALL the different data types in JavaScript (note that there are some that we did not discuss in class)?

The different types are Number, Boolean, Null, Symbol, and Undefined

Question 6

What is a boolean data type?

is a data that only have an true or false value

Question 7

What happens if you forget to put quotes around a string when you initialize a variable to a string value? How does JavaScript try to interpret this?
For example: var lastName = Jones;

Java will not see that as a straign but will see jones as an variale

Question 8

What character is used to end a statement in JavaScript?

Semicolin

Question 9

If you declare a variable, but do not initialize it, what value will the variable store?

The initial value is going to be Undefined

Question 10

What output will the following program produce? In other words, explain what you would see in the console log if you ran a program like this:


const firstTestScore = 98;
const secondTestScore = "88";
const sum = firstTestScore + secondTestScore;
console.log(sum);
console.log(typeof sum);

const firstTestScore = 98; This doesnot produce a code

Question 11

What output will the following program produce? In other words, explain what you would see in the console log if you ran a program like this:


const total = 99;
console.log("total");
console.log(total);

This doesnot produce a code

Question 12

What is the difference between these two variables?


const score1 = 75;
const score2 = "75";

First one is hidden in the console and second one will bring a pop up window

Question 13

Explain why the this code will cause the program to crash:


const score = 0;
score = prompt("Enter a score");

Because it is reassigned to a constant value

Coding Problems

Coding Problems - See the 'script' element below this h1 element. You will have to write some JavaScript code in it.

Here are some tips to help you with the coding problems:

To do this assignment, you'll need to know how to open the brower's developer tools (press F12) and look at the console log.
Pay extremely close attention to syntax! One little syntax error can mess up your entire program.
After you complete each problem, refresh the page in the browser and look in the console your log message and for errors.
If you have an error in the console, check the line number of the error then look for syntax errors on that line (and the line before and the line after that line).
If you get stuck on this assignment, please ask for help! Dealing with syntax errors can be extremely frustrating for beginners. It takes a lot of effort and support to get comfortable with the syntax of a language. Don't be afraid to ask for help, your success in this class will depend on your willingness to get help!