An Introduction to JavaScript

Question 1

javascript was created for what

Answer 1

scripting in the browser

Question 2

is javascript dynamic

Answer 2

yes meaning you can update elements on the fly

Question 3

javascript has properties of what two types of languages

Answer 3

oo and functional

Question 4

can u use js server side?

Answer 4

yes

Question 5

creating a javascript script

Answer 5

‘script type=”text/javascript”’

window.alert(“hi”);

‘/script’

Question 6

what does the type signify in declaring a javascript type=”text/javascript”

Answer 6

that everything inside is of type javascript

Question 7

good practice is to do what

Answer 7

put js code at end of page

Question 8

write line in js

Answer 8

writeln();

Question 9

declare a variable

Answer 9

var i=1;

Question 10

can you execute a js file outside of a browser

Answer 10

yes, using something like jsdb

Question 11

how to comment in js

Answer 11

single line //
multiline /*
*/
inline comments are available

Question 12

global variable how to

Answer 12

omit the var and just assign a name to a value

Question 13

how does var know its type

Answer 13

it is inferred based on what is passed to the variable

Question 14

get the type of a variable

Answer 14

typeof x;

Question 15

write a function in js with params and return value

Answer 15

function f(params){return params;}

Question 16

what is the global context for js

Answer 16

the window object

Question 17

null

Answer 17

primitive type that represents the absence of a value– evaluates to false

Question 18

undefined

Answer 18

primitive type represents an unknown or unassigned value

returns when non-existant item is called upon

also evaluates to false

Question 19

js pi

Answer 19

PI

Question 20

js method to return as fixed-point notation

Answer 20

tofixed(3)

Question 21

how are methods invoked on objects etc

Answer 21

the dot i.e. PI.toFixed(3)

Question 22

Get input from user

Answer 22

Prompt()– you can ALSo concat this with hi+ prompt to output hi and input, and even wrap it in an alert

Question 23

If you are writing in a .js file do you need to specify that it’s a script

Answer 23

No

Question 24

how to call a self written js file in same directory

Answer 24

‘script src=”name.js”'’script’

Question 25

how to log to console in js

Answer 25

console.log()

Question 26

is js whitespace sensative

Answer 26

no

Question 27

define a variable in js

Answer 27

var x=1;

Question 28

js array

Answer 28

var friends=[“nick”,”jim”,”brian”];

Question 29

js array methods

Answer 29

.length= how many in an array

Question 30

js array can hold another array t/f

Answer 30

t

Question 31

in js if you access an index outside of array max index,

Answer 31

it returns undefined

Question 32

js object has what

Answer 32

key pairs and values, an object is a lot like an array, but is assigned to a key

Question 33

declare a js array

Answer 33

var me{first_name: “x”, last name: “y”}

Question 34

how to access an attr of an array in js

Answer 34

var’s name.[key] like:

me.first_name;

Question 35

store an object in an object

Answer 35

var me{“Employee Number”:1}//wont work without quotes… to access use me[“Employee Number”] //again the quotes are important here

Question 36

change property in js array

Answer 36

me.first_name=”z”;

Question 37

what chracter is used to declare an object

Answer 37

{ }