A sample introduction to the meaning conflict of names in JavaScript

In yesterday's authoritative guide to Javascript study note 10: the object model enhanced by ECMAScript 5, there was a strange phenomenon with the debugging of a piece of code.

 
<script type="text/javascript"> 
function Person(){} 
var per = new Person; 
Object.defineProperties(per, 
{ 
"nickName": 
{ 
value:"Tom", 
writable:true 
}, 
"age": 
{ 
value:20, 
configurable:false, 
writable:false 
} 
}); 

var o = Object.getOwnPropertyDescriptor(per,"nickName"); 
alert(JSON.stringify(o)); 
</script> 

Running results in Google:
http://img.blog.csdn.net/20140529073008296? Watermark / 2 / text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvdTAxMTA0Mzg0Mw = = / font / 5 a6l5l2t/fontsize / 400 / fill/I0JBQkFCMA = = / dissolve / 70 / gravity Center
This result is correct, but change one place, the result is different

 
<script type="text/javascript"> 
function Person(){} 
var per = new Person; 
Object.defineProperties(per, 
{ 
"nickName": 
{ 
value:"Tom", 
writable:true 
}, 
"age": 
{ 
value:20, 
configurable:false, 
writable:false 
} 
}); 

var name = Object.getOwnPropertyDescriptor(per,"nickName"); 
alert(JSON.stringify(name)); 
</script> 

Operation results:
< img SRC = "border = 0 / / files.jb51.net/file_images/article/201405/201405291449142.gif? 2014429144927 ">  
Why is that? I just changed a simple variable name

The problem on the name, but I in JS, do not understand, no results found on the Internet, went to consult a brother behind, also put problems in the BBS on: http://bbs.csdn.net/topics/390799744? Page = 1 # post - 397474060,

Name is the window property that sets or returns the name of the window, and the data type is a string. Since the first sentence is function Person(){}, which is over, the following code is probably in the global context, which means that you think alert(json.stringify (name)); The output is the var name above, but it might actually be window.name. As for the output [Object Object], this type is the type of the value of the name.