Reference Type 3

REGEXP (); Used to build regular expressions, temporarily skip//

Legacy issues: Regular Expressions
Reference--http://www.jb51.net/tools/zhengze.html

5.5 Function type

1. "Function is object, function name is pointer";

2. Therefore, the function name is not bound to a function, that is, a function may have multiple functions name;

5.5.1 not overloaded//in-depth understanding

When declaring two functions with the same name, the following function overrides the previous function

5.5.2 function declarations and function expressions

1. There are differences between function declarations and function expressions

2. The parser will read the function declaration first and load it into the execution environment.

3. Function expression, only the line of code that executes to it will parse it.

4. In other words, declaring a function can not be reversed in order to define a function object after the function is called, but by a function expression.

Console.log (sum (10,10));     function sum (num1,num2) {      return num1 + num2;    } // declaring functions     Console.log (sum1 (10,10));     var function (num1,num2) {      return num1 + num2;    }; // Defining function Objects

The following section of code will perform an error ("No sum1 This object");

Internal properties of the 5.5.4 function

Two special properties:

1.arguments

2.this//refers to the environment object to which the function is executed

Properties and methods of the 5.5.5 function

Functions are also objects, so there are properties and methods

Each function consists of two properties:

1.length;

2.prototype

Reference Type 3