Theorie Javascript

Question 1

Javascript is a …

Answer 1

• weakly typed
• object-based
• dynamic
• mulit-paradigm

…scripting language

Question 2

Every browser on every OS runs

Answer 2

… JS

Question 3

Wikipedia lists 40 environments for “Uses outside Web pages”

And that is because…

Answer 3

…

• JS is small and lightweight
• JS runs inside hose environments

Question 4

Wikipedia lists 40 environments for “Uses outside Web pages”.
Typical uses are:

Answer 4

• embedded Scripting Language (JS inside Applications)
• Scripting Engine (JS on OS level)
• Application platform (JS as the main programming language)

Question 5

Client-side JS?

Answer 5

control of a browser and the DOM

eg. Webrosers

Question 6

Server-side JS?

Answer 6

control of objects relevant for servers

eg. Node.js

Question 7

Mobile Platforms

Answer 7

control of native APIs

eg. Apache Cordova/Phonegap

Question 8

What is ECMAScript

Answer 8

is a Standard for scripting languages

Question 9

Javascript is based..

Answer 9

on the ECMAScript standard

Question 10

ECMA International

Answer 10

European association for standardizing information and communication systems

Question 11

the ECMAScript spec is not for …

Answer 11

app developers, but for language implementors!

specification != Documentation

Question 12

companies can use the open standard language to develop their…

Answer 12

own implementation

Question 13

ECMAScript is also approved by…

Answer 13

the ISO

Question 14

Assignment

Answer 14

=

e.g. a = 41

Question 15

math

Answer 15

*
/

e.g.: a+1

Question 16

compound Assignment

Answer 16

*=
/=

e.g.: a+=1

Question 17

increment/decrement

Answer 17

e.g. a++

Question 18

equality

Answer 18

==

!= unequal
!== unequal

e.g.: a==42

Question 19

comparison

Answer 19

<
>
<=
>=

e.g.: a<=42

Question 20

logical

Answer 20

&& and
// or

Question 21

primitive types of Javascript

Answer 21

• numbers
• strings
• booleans (true and false)
• null
• undefined
• symbol

All other values are objects.

Question 22

Objects in Javascript are…

Answer 22

… mutable keyed collections

Question 23

an object is a …

Answer 23

.. container of properties

Question 24

a property has a …

Answer 24

name and a value

Question 25

a property name can …

Answer 25

be any string, including the empty string

Question 26

a property vlaue can be…

Answer 26

any Javascript value (except for undefined)

Question 27

objects have no

Answer 27

constraint on the name of new properties or on the values of properties

Question 28

objects can contain

Answer 28

other objects, to represent tree or graph structures

Question 29

object literals

Answer 29

• provide a very convenient notation for creating new object values
• is a pair of curly braces surrounding zero or more name/value pairs

e.g.:
var empty_object = {};

var stooge = {
“first-name”: “Jerome”,
“last-name”: “Howard”
};

Question 30

in JavaScript commas are used to

Answer 30

seperate the pairs