Question

Following is some codes and output from the Chrome Developers’ Console

Case 1:

var myarr = document.location.hostname.split(".");    //typed
undefined                                             //output
myarr[0]                                              //typed
"ptamz"                                               //output: ONE

Case 2:

var name = document.location.hostname.split(".");     //typed
undefined                                             //output
name[0]                                               //typed
"p"                                                   //output: TWO

Why are the two outputs (commented Output: ONE, and Output: TWO) different?

Screenshot:

Answer 1

name is a property of window. It appears that when you try to set that property to an array, the keys are joined with a comma (the result of calling toString on an array). So you are actually setting the window.name property to the concatenation of each element of document.location.hostname.split("."), separated by commas.

Here’s a screenshot from my Chrome console demonstrating what happens:

The reason name[0] then results in p is that you can access the characters of strings using square brackets:

name = "hello,world";
console.log(name[0]); //"h"

Edit

As others have mentioned, this will only be the case in the global scope. You are free to declare a variable named name inside a descendant scope. Although, obviously, omitting the var keyword in this case would still result in you accessing window.name:

function example() {
    var name = ["hello", "world"];
    console.log(name); //["hello", "world"]
}