A simple Script

Июль 31, 2022

Содержание

2. A simple Script First JavaScript Page First JavaScript Page document.write(" "); document.write("Hello World Wide Web"); document.write("
3. Embedding JavaScript Use the src attribute to include JavaScript codes from an external file. The included
4. Popup Boxes Alert box Confirm box Prompts box
5. alert(), confirm(), and prompt() alert("This is an Alert method"); confirm("Are you OK?"); prompt("What is your name?");
6. The typeof operator typeof operator used to find the type of a JavaScript variable.
7. Example
8. Undefined data type In JavaScript, a variable without a value, has the value undefined. The typeof
9. Null In JavaScript null is "nothing". It is supposed to be something that doesn't exist. Unfortunately,
10. Primitive Data
11. Complex Data
12. Line Breaks To display line breaks inside a popup box, use a back –slash followed by
13. JavaScript Objects Objects in real life is for instance Students Properties: name, ID, weigh, height etc.
14. JavaScript Objects You have already learned that JavaScript variables are containers for data values.
15. Objects Objects are variables too. Objects can contain many values
16. Example This code assigns many values (Fiat, 500, white) to a variable named car The values
17. Object Properties The name: values pairs are called properties. Property Property value
18. Object Methods Methods are actions that can be performed on objects. Methods are stored in properties
19. Example
20. Accessing Object Properties 2 ways Or
21. Accessing Object methods ObjectName.methodName()
22. Example
23. Do Not Declare Strings, Numbers, and Booleans as Objects! When a JavaScript variable is declared with
24. Conditional Statements Very often when you write code, you want to perform different actions for different
25. Types of conditional statements if statement - use this statement if you want to execute some
26. If statement Syntax and example If (expression) { Statements to be executed if expression is true
27. If .. Else statement
28. If…else if… statement syntax
29. If…else if… statement example
30. Switch Statement You should use the Switch statement if you want to select one of many
31. Switch statement’s syntax
33. The break Keyword When JavaScript reaches a break keyword, it breaks out of the switch block.
34. The default Keyword The default keyword specifies the code to run if there is no case
35. JavaScript Math Objects allows you to perform mathematical tasks on numbers Math.round(x) returns the value of
36. Math Properties (Constants) Math.E // returns Euler's number Math.PI // returns PI Math.SQRT2 // returns the
37. JavaScript Random Integers Math.random() used with Math.floor() can be used to return random integers. Math.floor(Math.random() *
39. Скачать презентацию

Слайд 2

A simple Script

First JavaScript Page

First JavaScript Page

Слайд 3

Embedding JavaScript
Use the src attribute to include JavaScript codes from an

external file.
The included code is inserted in place.

First JavaScript Program

Inside your_source_file.js
document.write("

");
document.write("Hello World Wide Web");
document.write("

");

Слайд 4

Popup Boxes
Alert box
Confirm box
Prompts box

Слайд 5

alert(), confirm(), and prompt()

Слайд 6

The typeof operator
typeof operator used to find the type of a

JavaScript variable.

Слайд 7

Example

Слайд 8

Undefined data type
In JavaScript, a variable without a value, has the

value undefined. The typeof is also undefined.

Слайд 9

Null
In JavaScript null is "nothing". It is supposed to be something

that doesn't exist.
Unfortunately, in JavaScript, the data type of null is an object.

Слайд 10

Primitive Data

Слайд 11

Complex Data

Слайд 12

Line Breaks
To display line breaks inside a popup box, use a

back –slash followed by the character n.
Example: alert(“Hello\n How are you?”);

Слайд 13

JavaScript Objects
Objects in real life is for instance Students
Properties: name, ID,

weigh, height etc.
Methods: eat, speak, walk, read, do something and etc.

Слайд 14

JavaScript Objects
You have already learned that JavaScript variables are containers for

data values.

Слайд 15

Objects
Objects are variables too.
Objects can contain many values

Слайд 16

Example
This code assigns many values (Fiat, 500, white) to a variable

named car

The values are written as name: value pairs (name and value separated by a colon)

Слайд 17

Object Properties
The name: values pairs are called properties.
Property
Property value

Слайд 18

Object Methods
Methods are actions that can be performed on objects.
Methods are

stored in properties as function definitions

Слайд 19

Example

Слайд 20

Accessing Object Properties
2 ways
Or

Слайд 21

Accessing Object methods
ObjectName.methodName()

Слайд 22

Example

Слайд 23

Do Not Declare Strings, Numbers, and Booleans as Objects!
When a JavaScript

variable is declared with the keyword "new", the variable is created as an object:

Слайд 24

Conditional Statements
Very often when you write code, you want to perform

different actions for different decisions. You can use conditional statements in your code to do this.

Слайд 25

Types of conditional statements
if statement - use this statement if

you want to execute some code only if a specified condition is true
if...else statement - use this statement if you want to execute some code if the condition is true and another code if the condition is false
if...else if....else statement - use this statement if you want to select one of many blocks of code to be executed
switch statement - use this statement if you want to select one of many blocks of code to be executed

Слайд 26

If statement Syntax and example
If (expression) {
Statements to be executed

if expression is true
}

Слайд 27

If .. Else statement

Слайд 28

If…else if… statement syntax

Слайд 29

If…else if… statement example

Слайд 30

Switch Statement
You should use the Switch statement if you want to

select one of many blocks of code to be executed.

Слайд 31

Switch statement’s syntax

Слайд 32

Слайд 33

The break Keyword
When JavaScript reaches a break keyword, it breaks out of the

switch block.
This will stop the execution of more code and case testing inside the block.
When a match is found, and the job is done, it's time for a break. There is no need for more testing

Слайд 34

The default Keyword
The default keyword specifies the code to run if there is

no case match:

Слайд 35

JavaScript Math Objects
allows you to perform mathematical tasks on numbers
Math.round(x) returns

the value of x rounded to its nearest integer
Math.round(4.7);    // returns 5 Math.round(4.4);    // returns 4:
Math.pow(x, y) returns the value of x to the power of y:
Math.pow(8, 2);      // returns 64
Math.sqrt(x) returns the square root of x:
Math.sqrt(64);      // returns 8
Math.abs(x) returns the absolute (positive) value of x:
Math.abs(-4.7);     // returns 4.7
Math.ceil(x) returns the value of x rounded up to its nearest integer:
Math.ceil(4.4);     // returns 5
Math.floor(x) returns the value of x rounded down to its nearest integer:
Math.floor(4.7);    // returns 4
Math.min() and Math.max() can be used to find the lowest or highest value in a list of arguments:
Math.min(0, 150, 30, 20, -8, -200);  // returns -200
Math.max(0, 150, 30, 20, -8, -200);  // returns 150
Math.random() returns a random number between 0 (inclusive), and 1 (exclusive):
Math.random();

Слайд 36

Math Properties (Constants)
Math.E // returns Euler's number Math.PI // returns PI Math.SQRT2 // returns the square

root of 2 Math.SQRT1_2 // returns the square root of 1/2 Math.LN2 // returns the natural logarithm of 2 Math.LN10 // returns the natural logarithm of 10 Math.LOG2E // returns base 2 logarithm of E Math.LOG10E // returns base 10 logarithm of E

Слайд 37

JavaScript Random Integers
Math.random() used with Math.floor() can be used to return

random integers.
Math.floor(Math.random() * 10); //returns a number between 0 and 9

A simple Script

Содержание

A simple Script First JavaScript PageFirst JavaScript Page <br> document.write("<hr>");<br></div></h2><div class="slides-content">document.write("Hello World Wide Web");<br> document.write("<hr>");<br>

First JavaScript Page

Embedding JavaScriptUse the src attribute to include JavaScript codes from an

Popup BoxesAlert boxConfirm boxPrompts box

alert(), confirm(), and prompt()<br>alert("This is an Alert method");<br>confirm("Are you OK?");<br>prompt("What</div></h2><div class="slides-content">is your name?");<br>prompt("How old are you?","20");<br>

The typeof operator typeof operator used to find the type of a

Example

Undefined data typeIn JavaScript, a variable without a value, has the

NullIn JavaScript null is "nothing". It is supposed to be something

Primitive Data

Complex Data

Line BreaksTo display line breaks inside a popup box, use a

JavaScript ObjectsObjects in real life is for instance StudentsProperties: name, ID,

JavaScript ObjectsYou have already learned that JavaScript variables are containers for

ObjectsObjects are variables too. Objects can contain many values

ExampleThis code assigns many values (Fiat, 500, white) to a variable

Object PropertiesThe name: values pairs are called properties.PropertyProperty value

Object MethodsMethods are actions that can be performed on objects.Methods are

Example

Accessing Object Properties2 waysOr

Accessing Object methodsObjectName.methodName()

Example

Do Not Declare Strings, Numbers, and Booleans as Objects!When a JavaScript

Conditional StatementsVery often when you write code, you want to perform

Types of conditional statements if statement - use this statement if

If statement Syntax and example If (expression) {Statements to be executed

If .. Else statement

If…else if… statement syntax

If…else if… statement example

Switch StatementYou should use the Switch statement if you want to

Switch statement’s syntax

The break KeywordWhen JavaScript reaches a break keyword, it breaks out of the

The default KeywordThe default keyword specifies the code to run if there is

JavaScript Math Objectsallows you to perform mathematical tasks on numbersMath.round(x) returns

Math Properties (Constants)Math.E // returns Euler's number Math.PI // returns PI Math.SQRT2 // returns the square

JavaScript Random IntegersMath.random() used with Math.floor() can be used to return

Похожие презентации

A simple Script

First JavaScript Page

First JavaScript Page

Embedding JavaScript
Use the src attribute to include JavaScript codes from an

Popup Boxes
Alert box
Confirm box
Prompts box

alert(), confirm(), and prompt()

The typeof operator
typeof operator used to find the type of a

Undefined data type
In JavaScript, a variable without a value, has the

Null
In JavaScript null is "nothing". It is supposed to be something

Line Breaks
To display line breaks inside a popup box, use a

JavaScript Objects
Objects in real life is for instance Students
Properties: name, ID,

JavaScript Objects
You have already learned that JavaScript variables are containers for

Objects
Objects are variables too.
Objects can contain many values

Example
This code assigns many values (Fiat, 500, white) to a variable

Object Properties
The name: values pairs are called properties.
Property
Property value

Object Methods
Methods are actions that can be performed on objects.
Methods are

Accessing Object Properties
2 ways
Or

Accessing Object methods
ObjectName.methodName()

Do Not Declare Strings, Numbers, and Booleans as Objects!
When a JavaScript

Conditional Statements
Very often when you write code, you want to perform

Types of conditional statements
if statement - use this statement if

If statement Syntax and example
If (expression) {
Statements to be executed

Switch Statement
You should use the Switch statement if you want to

The break Keyword
When JavaScript reaches a break keyword, it breaks out of the

The default Keyword
The default keyword specifies the code to run if there is

JavaScript Math Objects
allows you to perform mathematical tasks on numbers
Math.round(x) returns

Math Properties (Constants)
Math.E // returns Euler's number Math.PI // returns PI Math.SQRT2 // returns the square

JavaScript Random Integers
Math.random() used with Math.floor() can be used to return