Data type of JS base

One: JavaScript data type: string, Number, Boolean, array, object, Null, Undefined

JavaScript string;

var carname= "Bill Gates";

JavaScript numbers;

var x1=34.00; //Use a decimal point to write

var x2=34; //Do not use decimal point to write

JavaScript Boolean;

var x=true;var y=false

JavaScript arrays;

var cars=new Array ();
Cars[0]= "Audi";
Cars[1]= "BMW";
Cars[2]= "Volvo";

JavaScript object;

var person={firstname: "Bill", LastName: "Gates", id:5566};
Name=person.lastname;
name=person["LastName"];

Undefined and Null;

Undefined This value indicates that the variable does not contain a value.

You can empty a variable by setting the value of the variable to null.

Declaring variable types

When you declare a new variable, you can use the keyword "new" to declare its type:

var carname=new string;var x=      new Number;var y=      new Boolean;var cars=   new Array;var person= new Object;

Two: JS operator

Base: +,-, *,/,%,++,--; =,+=,-=,*=,/=,%=;

Advanced: ECMAScript unary operator, ECMAScript bitwise operator, ECMAScript Boolean operator, ECMAScript multiplicative operator, ECMAScript additive operator, ECMAScript relational operator, ECMAScript operator, ECMAScript conditional operator, ECMAScript assignment operator, ECMAScript comma operation character;