Web Programming - Week 3

Question 1

What are HTML Events

Answer 1

Activities performed by user to control the page which can execute JavaScript code

Question 2

Syntax of defining an event attribute

Answer 2

< element eventname = code >

Question 3

Common HTML events

Answer 3

onchange
onclick
onmouseover
onmouseout
onkeydown
onload

Question 4

How to define an object

Answer 4

var ObjectName = new Object();
OR
var ObjectName = {..} comma instead of semi colon

Question 5

What is the purpose of “this” in a function

Answer 5

Refers to the owner of the function

Question 6

JavaScript prebuilt objects

Answer 6

Array - Makes a list with [] or ()
Date - (YY/MM/DD)
Maths
String
Number
JSON

Question 7

Common String Methods

Answer 7

length
indexOf(string)
toUpperCase()
trim()

Question 8

Common Number Methods

Answer 8

toString()
toFixed(number)

Number()

parseInt()
parseFloat()
isNan()

Question 9

Common Array Methods

Answer 9

toString()
join(separator)

pop() - Removes and returns last value
push() - Adds new value
shift() - Removes first value

unshift() - Adds new element at beginning
reverse()

Question 10

Syntax of calling sort

Answer 10

arr.sort([compareFunction])

compareFunction defines alternative sort order

Question 11

Compare Function Structure

Answer 11

array.sort(function(a,b){
return a - b;
});

Question 12

Arrow Compare Function Structure

Answer 12

array.sort((a,b) => a - b);

Question 13

Common Math Methods

Answer 13

PI
round()
min()
max()
random()

Question 14

Creating a Date object

Answer 14

new Date(); - Today's date
new Date(year, month, day, hours...)
new Date(dateString);

Question 15

Common Date Methods

Answer 15

getFullYear()
getMonth()
toString()

Question 16

JSON syntax

Answer 16

{“property”:value, “property”:value, etc.}

Question 17

Two important JSON methods

Answer 17

JSON.stringify() - Converts object to string

JSON.parse() - Converts string to object

Question 18

What is a property

Answer 18

A value that you can get or set

Question 19

What is a method

Answer 19

An action that you can do

Question 20

Document Object Methods

Answer 20

document.getElementById(ObjectID)

var element = document.getElementById(ObjectID);

document.getElementsByTagName(name)

var paragraph = document.createElement(“p”);

var element = document.getElementByClassName(Classname)

Question 21

What does querySelector() do

Answer 21

Returns the first element that matches a specified CSS Selector(s) in the document

Question 22

What does document.querySelector(“p.myP”) do

Answer 22

Returns the first paragraph with class “myP”

Question 23

What does querySelectorAll() do

Answer 23

Returns all elements that match a specified CSS Selector(s) in an array

Question 24

What is the syntax for an event listener for an existing function

Answer 24

element.addEventListener(event,function_name);

Question 25

What is the syntax for an event listener for a new function

Answer 25

element.addEventListener(event, function(){

});