Javascript DOM Programming Art ——— Summary-1

The first chapter:

1.DOM: is a set of methods for abstracting and conceptualizing the content of a document, which is an API.

2.W3C definition of DOM: An excuse that is independent of the system platform and programming language programs and scripts can dynamically access and modify document content, structure, and style through this interface.

3.Ajax: Asynchronous data transmission, H5 <canvas> elements have a perfect drawing ability.

4.JavaScript Basic Syntax:<1> Comment: Single line comment "//"

Multiline comment "/* * *"

<2> variables: Allows you to assign values directly to a variable without having to declare it beforehand, in JavaScript before assigning a value to a variable is declared, the assignment action will be automatically declared for that variable.

　　　　　　　　　　　　　　　　Note: As a good coding habit, the keyword VAR is used to declare a variable at the first time it is assigned a value.

<3> data type:JavaScript does not require a type declaration, a weak type.

String (String), numeric (number), Boolean (Boolean), Array (object)

Note: An object is a very important data type that is contained in the data Access form: 1. Properties 2. Method.

A property is a variable that is subordinate to a particular object, by a function that only a particular object can call.

<4> operators: Arithmetic operators, comparison operators, logical operators,

<5> Conditional statement: Used as a judgment.

<6> function:

<7> variable scope: Global variables and local variables.

<8> built-in objects: pre-defined objects that can be used as objects. such as: Array.

<9> Host object: A pre-defined object provided by the browser. such as: Form, Element

Javascript DOM Programming Art ——— Summary-1