Chapter 1

Question 1

Official name for JavaScript

Answer 1

ECMAScript

Question 2

ECMAScript

Answer 2

A standardized version of javascript that is compatible with various browsers.

Question 3

//

Answer 3

Single line comments start with //.

Any text between // and the end of the line will be ignored by JavaScript (will not be executed).

Question 4

/* */

Answer 4

Multi-line comments start with /* and end with */.

Any text between /* and */ will be ignored by JavaScript.

Question 5

A variable is declared (created) with a

Answer 5

;

Ex. var x;

Question 6

Describe: x=3+y;

Answer 6

Assigning a value to the variable x

Question 7

Describe: foo(x,y);

Answer 7

calling function foo with parameters x and y

Question 8

obj.bar(3)

Answer 8

calling method ‘bar’ of object ‘obj’

Question 9

conditional statement example

Answer 9

if (x===0) {
return “Try Again”;
}

Question 10

= vs ===

Answer 10

=== is more strict of an equality

Question 11

x+=1 equivalent

Answer 11

x=x+1

Question 12

.length

Answer 12

outputs the number of characters in a variable or value
Ex: 
var str="abc"
str.length
3 //output is 3
Ex. "abc".length
3 //output is 3

Question 13

how to assign a value to a property

Answer 13

you must declare an object, add a property to the object, then assign a value to the property
Ex.
var obj={}; //empty object
obj.foo=123; // create property foo, set it to 123
obj.foo
123 //output is 123

Question 14

.toUpperCase()

Answer 14

turns precedent characters to all capital letters
“hello”.toUpperCase()
HELLO

Question 15

can two empty objects be strictly equal to each other

Answer 15

No. Each object has a unique identity and is only strictly equal to itself
ex.:
var obj1={};
var obj2={};
obj1===obj2
false

Question 16

string example

Answer 16

“abc”

Question 17

boolean example

Answer 17

4===2;
false
or 2===2
true

Question 18

how to add multiple properties to an object

Answer 18

var obj={
firstName: "ayden",
lastName: "licea"};

Question 19

operator for describing the “type” of value

Answer 19

typeof
ex.
typeof true
‘boolean’

Question 20

or

Answer 20

||

Question 21

not

Answer 21

!

Question 22

increment

Answer 22

++ or –

Question 23

remainder

Answer 23

%

Question 24

new line

Answer 24

<br></br>

Question 25

how to access single characters of a string

Answer 25

var str = 'abc'; str[ 1] 'b'

Question 26

how to count number of characters in a string

Answer 26

ex. "abc".length 3

Question 27

how to concatenate strings in multiple steps

Answer 27

``` use += ex. var str = ''"; str += 'Multiple '; str += 'pieces '; str += 'are concatenated.'; str 'Multiple pieces are concatenated.' ```

Question 28

how to slice characters out of a string

Answer 28

'abc'. slice( 1) // copy a substring 'bc' 'abc'. slice( 1, 2) // 1=slice starting point. 2=slice ending point 'b'

Question 29

how to get rid of white space in a string

Answer 29

.trim //removes white space from the beginning and/or end of a string ex. var str = " Hello World! "; alert(str.trim());

Question 30

how to create a button

Answer 30

button title

Question 31

how to add functionality to a button

Answer 31

``` onclick Try it //executes a function when user clicks //button named 'Try it' ```

Question 32

how to find a character location in a string

Answer 32

.indexOf > 'abc'. indexOf(' b') // find a string 1

Question 33

how to add items to the end of an array

Answer 33

``` .push() ex. var fruits = ["Banana", "Orange", "Apple", "Mango"]; fruits.push(",Kiwi"); Banana,Orange,Apple,Mango,Kiwi ```

Question 34

what base is the length property

Answer 34

``` one-based ex. var arr = [1, 2, 3, 4, 5]; console.log(arr.length); //4 ```

Question 35

what base is an array index

Answer 35

zero-based

Question 36

slice() method

Answer 36

The slice() method returns the selected elements in an array, as a new array object. The slice() method selects the elements starting at the given start argument, and ends at, but does not include, the given end argument. ex. var arr = [1,2,3,4,5,6]; console.log(arr.slice(2,5)) //3,4,5 ex. var animals = ['ant', 'bison', 'camel', 'duck', 'elephant']; console.log(animals.slice(2)); //camel, duck, elephant ``` console.log(animals.slice(2, 4)); //camel, duck ```

Question 37

.trim()

Answer 37

tims whitespace ``` var str = " Hello World! "; alert(str.trim()); //Hello World! /* instead of: Hello World!*/ ```

Question 38

.toUpperCase()

Answer 38

``` 'mjölnir'. toUpperCase() //MJÖLNIR ```

Question 39

.indexOf()

Answer 39

``` 'ayden'.indexOf('d'); //2 ```

Question 40

how to get a negative number output from .indexOf()

Answer 40

The indexOf method returns the beginning of the substring in the String object. If the substring is not found, -1 is returned. ``` 'abcd'.indexOf('j'); //-1 ```

Question 41

and

Answer 41

&&;

Question 42

else if statement format

Answer 42

``` if () { //then } else if () { //else-if } else { //else } ```

Question 43

switch statement format

Answer 43

``` ex. 1 switch (expression) { case value1: //Statements executed when the //result of expression matches value1 break; case value2: //Statements executed when the //result of expression matches value2 break; ``` ``` ex. 2 case valueN: //Statements executed when the //result of expression matches valueN break; default: //Statements executed when none of //the values match the value of the expression break; } ex. 3 var expr = 'Papayas'; switch (expr) { case 'Oranges': console.log('Oranges are $0.59 a pound.'); break; case 'Mangoes': case 'Papayas': console.log('Mangoes and papayas are $2.79 a pound.'); // expected output: "Mangoes and papayas are $2.79 a pound." break; default: console.log('Sorry, we are out of ' + expr + '.'); } ```

Question 44

for loop format

Answer 44

for (initial statement, condition, post-iteration) { code block to be executed } ``` ex. var cars = ["BMW", "Volvo", "Saab", "Ford", "Fiat", "Audi"]; var text = ""; var i; for (i = 0; i < cars.length; i++) { text += cars[i] + "
"; } document.getElementById("demo").innerHTML = text; } ``` ``` /*output BMW Volvo Saab Ford Fiat Audi */ ex2 ``` ``` for (let i = 0; i < 4; i++) { document.write(i); } ``` //output = 0123

Question 45

x += y equivolent

Answer 45

x = x + y

Question 46

while loop

Answer 46

``` ex. 1 var i= 0; while (i < 10) { document.write(i); i++; } ```

Question 47

break;

Answer 47

ends a loop ex. if (a<10) { break;}

Question 48

two types of javascript values

Answer 48

text and numbers

Question 49

how to make a variable a string

Answer 49

make it equal to "" ex. var str="";