July 14: JS's basic syntax

First of all, it is the most recent course arrangement:

JS basic Syntax →bom→dom→dom style sheet →js event →js form → regular expression;

Here's what you'll learn today:

First, the introduction of JS

JS is a weakly-typed interpretation language that uses var to define variables. JS to run in a Web environment, and Java can be used on any platform

Second, the original data type JS

1. Undefined: undefined type and value, no return value
2. Null: Represents an object that does not exist
3. Boolean: Only 2 values of true and False
4. Number: Numeric, can represent 32-bit integers and 64-bit floating-point numbers
5. String: Character type

Iii. Types of conversions

1. Boolean (value): Converts the given value to a Boolean type
2. Number (value): Converts the given value to a digital type
3. String (value): Converts the given value to a string type
4. parseint (value): Converts the given value to an integer number
5. Parsefloat (value): Converts the given value to a floating-point type

Iv. native Objects

1. Array: Create an array in JS

var arr = new Array (value);

2. Date: Current system time

GetMonth is from 0月-November;

3. encodeURI () encoding; decodeURI decoding

Five, function: a set of statements that can be run anywhere, is the core of JS

Function name (parameter) {statement}

July 14: JS's basic syntax