DOM Scripting 2nd - Notes - 作业部落 Cmd Markdown 编辑阅读器

@daixuan1996 2015-03-14T23:46:23.000000Z 字数 2288 阅读 700

DOM Scripting 2nd - Notes

Author: Dai Xuan

Notation: There is a bad view on github...

Chapter1
- Concepts:
  - DOM: document object model
  - BOM: browser object model
  - JavaScript == ECMAScript, JScript(M$)
  - DHTML: Dynamic HTML, a shorthand term for describing the combination of HTML, CSS, and JavaScript.
- 1999.10, W3C putting together a standardized DOM. (DOM Level 1)
- DOM is a kind of API.
- Webkit: Safari Chrome Firefox
  Gecko: Firefox
  Trident: IE
Chapter2
- Better way to place JavaScript:
```
    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="utf-8">
        <title>test</title>
    </head>
    <body>
        ...
        <script src="test.js"></script>
        
    </body>
    </html>
```
- JavaScript is a interpreted language, which interpreted by the web browser.
- Semicolon(;) is not necessary but advised.
- Comment:
```
    // comment1 -line
    /* comment2 - block*/
```
- JavaScript is a weakly typed language.
- Data Type
  - String, '' or "". Better to be consistent.
  - Number, interger or float, positive or negative.
  - Boolean, true or false.
  - Array, very free.
```
    var a = Arrary(args);              // arg is optional
    var b = [[1, 2, 3], "what", true]; // free, numeric array
    var c = Array();                   // associative array
    c["name"] = "H";
    c["year"] = 1999;
```
  - Object, a group of multiple values under the same name. Each one of the value is a property of the object.
```
    var a = Object();
    a.name = "H";
    a.year = 1999;
    var b = { name: "H", year: 1999};
    var c = {};
    c.pro = a;  // c.pro.name == "H"
```
- Operations
  - Arithmetic Operators, + - / * = ++ -- +=
  - Comparision Operators, > >= < <= ==(value) ===(value and type)
  - Logical Operators, && || !
- Statements
  - Conditional Statements, if...else if...else
  - Looping Statements, while / do...while / for
- Function, a group of statements that can be invoked from anyware in your code.
  - There are many built-in funnction, like alert().
  - Function can be used as a data type.
- Variable Scope
  - A global variable can be referenced from anywhere in the script, even within functions. It has a global scope.
  - A local variable exists only within the function in which it is declared. It has a local scope.
  - Use var to declare a local variable.
- Objects, a self-contained collection of data, which comes in two forms: properties and methods.
  - A property is a variable belonging to an object.
  - A method is a function that the object can invoke.
  - Object.property
  - Object.method()
  - An instance is an individual example of a generic object.
```
    var you = new ObjectName;
```
  - User-defined Objects
  - Native Objects
    - Array
      - property: length
      - method: sort()
    - Date, can be used to store and retrieve information about a specific date and time.
      - method: getDay(), getHours(), getMonth()
    - Math
      - method: round()
  - Host Objects, objects that are supplied by the web browser. Like Form, Image, and Element...
Chapter3

DOM Scripting 2nd - Notes

Author: Dai Xuan

Notation: There is a bad view on github...

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