used as part of web browsers, whose implementations allow client-side
to interact with the user, control the browser and asynchronously communicate with server-side.JavaScript syntax was influenced by C.
Разделы презентаций
- Разное
- Английский язык
- Астрономия
- Алгебра
- Биология
- География
- Геометрия
- Детские презентации
- Информатика
- История
- Литература
- Математика
- Медицина
- Менеджмент
- Музыка
- МХК
- Немецкий язык
- ОБЖ
- Обществознание
- Окружающий мир
- Педагогика
- Русский язык
- Технология
- Физика
- Философия
- Химия
- Шаблоны, картинки для презентаций
- Экология
- Экономика
- Юриспруденция
Module 1: Introduction to JavaSript D. Petin 04/2014
Содержание
- 1. Module 1: Introduction to JavaSript D. Petin 04/2014
- 2. AgendaBasic InformationIncluding JS Code into HTMLCommentsVariablesData TypesType Casting
- 3. Basic Information
- 4. Basic informationJavaScript - dynamic computer programming language.It
- 5. Basic informationJS take many names and naming
- 6. Including JS Code into HTML
- 7. Including of JavaScriptExist three ways to include
- 8. Inline including…. Unfortunately, this is the worst
- 9. Inside tag f() ;Sometimes it makes sense.
- 10. In separate fileThis is the best way.
- 11. Comments
- 12. CommentsComments - part of the program text
- 13. Variables
- 14. VariablesVariable – symbolic name associated with a
- 15. Declaration and initializationvar – special keyword for
- 16. Global and localJavaScript has two types of
- 17. Data Types
- 18. Data typesJavaScript have 6 base data types:
- 19. Number, Boolean and Stringvar n = 10;
- 20. Null and Undefinedvar n = null; //null
- 21. Type Casting
- 22. Type casting
- 23. Type castingvar a, b, c; a =
- 24. Type castingBase rules of typing casting:All scalar
- 25. Слайд 25
- 26. Скачать презентанцию
AgendaBasic InformationIncluding JS Code into HTMLCommentsVariablesData TypesType Casting
Слайды и текст этой презентации
Слайд 4Basic information
JavaScript - dynamic computer programming language.
It is most commonly
JavaScript syntax was influenced by C.
Слайд 5Basic information
JS take many names and naming conventions from Java,
but the two languages are otherwise unrelated and have very
different semantics.JavaScript is a prototype-based scripting language with dynamic typing.
JS supported object-oriented, imperative and functional programming styles.
[1]
[2]
[3]
Слайд 7Including of JavaScript
Exist three ways to include script into HTML
page:
Inline in HTML
Inside tag
In separate
file [1]
[2]
[3]
Слайд 8Inline including
….
Unfortunately, this is the worst
solution.
Holistic code will be broken into smaller parts.
Such
parts are difficult to test and maintain. :(
Слайд 9Inside tag
f() ;
Sometimes it makes sense.
But in the
general case, page size will be increased
and, as a result,
its performance reduced.
Слайд 10In separate file
This is the best way.
Code is holistic.
It’s easy to test and maintain.
In addition, separated files
are cached by the browser. This improves performance. :)
Слайд 12Comments
Comments - part of the program text which will be
ignored by language interpreter
The /* characters, followed by any sequence of
characters (including new lines), followed by the */ characters.The // characters, followed by any sequence of characters, but only in current line. Therefore, it is commonly called a "single-line comment."
[1]
[2]
[3]
Слайд 14Variables
Variable – symbolic name associated with a value and whose
associated value may be changed.
Declaration – process of variable's specifying.
Usually declaration consist of defining: type, name and default value of variable. A process in which a variable is set to its first value is called initialization.
[1]
[2]
[3]
Слайд 15Declaration and initialization
var – special keyword for declaration of variables
In
JavaScript
var variable; //declaration
variable = 10;
//initializationOr quickly
var variable = 10;
[1]
[2]
[3]
Слайд 16Global and local
JavaScript has two types of variables:
global -
exist in memory and is available at all times of
the program. In JS it's a variables of page.local - exist in memory and is available only in block when variable is defined. In JS it's defined in function variables.
[1]
[2]
Слайд 18Data types
JavaScript have 6 base data types:
Number – scalar
type for integer and real digits
Boolean – scalar type
for logical valuesString – special type for work with text information
Undefined – special type for uninitialized variables
Null – special type for "cleaning" of variables
Object – complex type for service and user needs
Слайд 19Number, Boolean and String
var n = 10; or var n
= Number(10);
//number values for example: -1, 10, 3.14, Nan,
Infinityvar s = “text”; or var s = String(“text”);
//string values for example: “”, “text”, ‘text’
var b = true; or var b = Boolean(true);
//bollean values: true and false
[1]
[2]
[3]
Слайд 20Null and Undefined
var n = null;
//null variables can have
only null value
var u;
// created and uninitialized
And Object type…
but it will be reviewed in future :)[1]
Слайд 23Type casting
var a, b, c;
a = 10;
b =
true;
c = a + b;
var a, b, c;
a
= 10; b = true;
c = a + Number(b);
Exist two types of casting:
Implicit
Explicit
But both ways given c =11 as a result!
[2]
[1]
[3]
Слайд 24Type casting
Base rules of typing casting:
All scalar types try to
convert itself to largest scalar type: Boolean to Number, Number
to String.If Boolean converted to String it at first converted to Number and after them Number to String.
In mathematical operations (excluding +) String should be converted to Number.
Null and Undefined converted to String as “null” and “undefined”, and to Number as a 0 and NaN
[1]
[2]
[3]
[4]
