"JavaScript Advanced Programming" Reading Notes (1) ECMAScript Basics_Javascript Skills

2.1 Syntax
Case-sensitive, weak type of variables, semicolon at the end of the line is optional, comments are double slashes, brackets indicate code blocks

2.2 Variables
Variables are declared with var. Naming rules: The first character must be a letter, underscore, or dollar sign; the remaining characters can be an underscore, dollar sign, or any alphabetic or numeric character.

Variable naming convention:

Camel notation: the first letter is lowercase, and subsequent words begin with capital letters. For example: var myTestValue=0,mySecondTestValue="hi";

Pascal notation: the first letter is capitalized, and subsequent words begin with capital letters. For example: var MyTestValue=0,MySecondTestValue="hi";

Hungarian type notation: append a lowercase letter (or sequence of lowercase letters) before a variable named in Pascal notation to indicate the type of the variable. For example, i represents an integer and s represents a string, as shown below:

var iMyTestValue=0,sMySecondTestValue="hi";

Define the prefix used by ECMAScript variables using Hungarian type notation As follows:

Type: Array Prefix: a Example: aValues ​​

Type: Boolean Prefix: b Example: bFound

Type: Float Prefix: f Example: fValue

Type: Function Prefix: fn Example: fnMethod

Type: Integer Prefix: i Example: iValue

Type: Object Prefix: o Example: oType

Type: Regular Prefix: re Example: rePatten

Type: String Prefix: s Example: sValue

Type: Variable Prefix: v Example: vValue

2.3 Key Word
ECMA-262 defined keywords are:

break case catch continue default delete do do else finally for function if in instanceof return switch this throw try typeof while with

2.4 Reserved words
The reserved words in ECMA-262 version 3 are:

abstract boolean byte char class const debugger double enum export extends goto implementations import int interface long native package　private　protected　public　short　static　super synchronized throws transient volatile

2.5 Primitive and reference values ​​
Primitive values ​​are simple data segments stored in the stack, that is, their values ​​are stored directly in variable accesses location.

The reference value is an object stored in the heap. That is to say, the value stored in the variable is a pointer (point) pointing to the memory where the object is stored.

Author: Tian Xingjian, self-improvement