JS basis - common data types

1. Common data types

　　Primitive types (basic types) comprises: number, string, boolean, null, undefind

　　Reference types include: object, wherein the object is divided Function, Array, Date ......

 

　　Primitive types (basic types): Access by value, the actual value may be stored in the operation variables. Summary of the original type null and undefined special.

　　Reference types: access by reference, at the time of the operation object, the object is actually in reference to the operation rather than the actual object.

 

2. implicit conversion

　　a === b

　　It indicates that the values ​​of a and b are equal, and also consistent with the data type. For example:

1 === "1"　　//false

　　　　a == b

　　　　Represents said, as long as the values ​​of a and b are the same as on the line; a and b are inconsistent with the type of data, will first try to look implicit conversion.

1 == "1"　　//true