为什么JavaScript split（）会使用不同的变量名生成不同的输出？ [英] Why does JavaScript split() produce different output with different variable names?

问题描述

以下是Chrome开发者控制台的一些代码和输出

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

案例1：

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

案例2：

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

为什么两个输出（注释输出：ONE和输出：TWO）不同？

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

屏幕截图：

推荐答案

name 是 window 的属性。看来，当您尝试将该属性设置为数组时，键将以逗号连接（调用 toString ）。所以你实际上是将 window.name 属性设置为 document.location.hostname.split（。）的每个元素的串联，以逗号分隔。

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.

这是我的Chrome控制台的屏幕截图，展示了会发生什么：

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

原因 name [0] 然后结果 p 是你可以使用方括号访问字符串的字符：

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"

修改

正如其他人所提到的，这只是全球范围内的情况。您可以在后代范围内声明名为 name 的变量。虽然，在这种情况下，省略 var 关键字仍会导致您访问 window.name ：

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"]
}

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