JavaScript Midterm

HTML=structure/framework

CSS=design

JavaScript=interactive features

Uses a model of an object; object-oriented programing

*objects are things:

-they have properties, events, and methods

-properties+events+methods=object

*involve user interactions

-programmers choose what events trigger a specific section of code

-scripts can trigger different types of functionality

*how people interact with objects

-second part of the code after period (member operator)

   event                 method

|------------| |-----------------------------|

document.write(‘Good afternoon!’)

Events trigger methods and methods retrieve or update an objects properties

store temporary bits of information to perform a task

variable name

|----| |---------|

var boldColor

var

let

const

give it a name (identifier)

data that is stored within the variable

a value must be assigned to a variable

Numeric, strings, boolean

can be decimals or negative numbers

cannot have commas

consist of letters and characters

add content to a page

always within ‘single’ or “double” quotation marks

can only have 1 of 2 values, true or false

a special type of variable that stores a list of values

always in [square brackets] or array()

used for a list or set of values, useful if the number of items will vary

always separated by commas, uses ‘single’ or “double” quotes

index starts with 0

ex:

let stopLight;

stopLight = [‘yield’, ‘stop’, ‘walk’];

stopLight[1] = ‘go’

stopLight has an index of 1 which would be stop, but it is set equal to go, so stop is being changed to go making the stopLight array [‘yield’, ’go’, ‘walk’]

result in a single value

used to create a single value from one or more values

assignment (=)

string (+)

logical (&&)

comparison (> | <)

=

assigns a value to a variable

+

combines two strings

&&

combines expressions as true or false (boolean)

<

compares values

a series of statements that are grouped to perform a task

conditions determine a path to take

returns a true or false value (boolean)

if a condition is met, then a statement is executed

else code executes a different statement (AKA code skips ahead)

if statements compares value to true

else if the value is false

document object model

views and changes the output of HTML without actually changing the original HTML

document node