JavaScript data types

1. Basic data type (return data type with typeof, start with lowercase letters)

Undefined

Boolean

String

Number

Object

The data type of the Null:null is object.

2.Number type

Includes integral and floating-point types.

var box=9.0;

alert (box);//auto-Convert to Integer 9 output

var num=1.12e3;//Scientific counting method

The number valid range is obtained through max_value and Min_value, and you can isfinite the function to return if the range is exceeded.

3.NaN (not a number)

Used to indicate that a numeric type should be returned but not returned. The isNaN function returns True or FALSE.

var box=0/0;

alert (box);//Return Nan

var box= ' 12sdffs ';

Alert (parseint (box));//output 12,parseint can also return octal and 16 binary numbers

4.String type

In ECMAScript, single and double quotation marks are the same resolution mechanism.

The ToString method can convert a value to a string.

5.Object type

Note the empty object is null and the empty object is Var obj={};

objects can be created by using the new operator.

var box=new Object ();

alert (box);

You can also pass parameters to create objects, such as:

var box=new Object (2);

alert (box); Print out 2

Alert (typeof (Box));//Print Object

JavaScript data types