HTML Dom tutorial 49-javascript number object

HTML Dom tutorial 49-javascript number object

 

In JavaScript, numbers are a basic data type.

Javascript supports the number object, which is the packaging object of the original value.

When necessary, JavaScript will automatically convert between the original data and the object.

The constructor number () can be used directly as a conversion function instead of the new operator. When you call number () in this way, it will convert its parameter into a number, and then return the converted original value (or Nan ).

1: Number object Method

Method	Description	FF	IE
Tostring	Converts a number to a string and uses the specified base number.	1.0	4.0
Tolocalestring	Converts a number to a string in the format of a local number.	1.0	4.0
Tofixed	Converts a number to a string. The result is a number of the specified digits after the decimal point.	1.0	5.5
Toexponential	Converts a number to a string and returns an exponential notation. the decimal point has a specified decimal number.	1.0	5.5
Toprecision	Converts a number to a string that contains a valid number of specified digits. The exponential or fixed-point counting method is used to determine the value of a number and the specified number of valid digits.	1.0	5.5
Valueof	Returns the basic numeric value of A number object.	1.0	4.0

2: Number Object Attributes

Attribute	Description	FF	IE
Max_value	The maximum number that can be expressed.	1.0	4.0
Min_value	The smallest number that can be expressed.	1.0	4.0
Nan	Non-numeric value.	1.0	4.0
Negative_infinity	Negative infinity. This value is returned when overflow occurs.	1.0	4.0
Positive_infinity	Positive infinity. This value is returned when overflow occurs.	1.0	4.0

Note: The preceding five constants are the attributes of the constructor number (), rather than the attributes of a single number object.

For example, the max_value attribute is correct:

 
VaR big = number. max_value
 

However, this is incorrect:

 
VaR n = new number (2 );

VaR big = n. max_value