View the execution environment using the JS interpreter rhino

Rhino is a Mozilla open-source javascript interpreter written by Java.

Document address https://developer.mozilla.org/en/Rhino_documentation

Installation Method http://www.terminally-incoherent.com/blog/2008/01/08/rhino-scripting-java-with-javascript

Install.

Sudo apt-Get install rhino in Ubuntu

Then write a. js file with the following content:

 
Print ("Hello World ")
 

Enter rhino A. js in the terminal. The input Hello world is displayed.

In rhino, the variable object in the JS execution environment can be returned. Pass _ parent __

 
Function f () {var Bob = 'hello'; var inner = function () {}; var parent = inner. _ parent __; var contents = ''; For (K in parent) contents + = K +''; print (contents);} f ();
 

Output: arguments Bob inner parent Contents

Take a lookCodeWhat will be output?

Function A () {var a2 = "in"; return function () {var B = 2; return B;} var B = a (); var contents = ''; for (K in B. _ parent _) contents + = K + ''; print (contents)
 

Output: arguments A2

What are described above? The scope chain of function B has been created when the function is defined.