[英]How to reference a global scope variable into the local scope?
var b=1;
function someFunc(b) {
//here
}
I want to be able to reference the variable b that is defined outside the function. 我希望能够引用在函数外定义的变量b。 How can this be done in javascript?
怎么能在javascript中完成?
You need to access it via the global object
, which is window
in a browser and global
in node.js for instance. 您需要通过
global object
访问它,例如,浏览器中的window
和node.js中的global
window
。
var b=1;
function someFunc(b) {
alert( window.b ); // or console.log( global.b );
}
Why ? 为什么? Well, the such called Activation Object (in ES3) or the Lexical Environment Record (ES5) will overlap the variable name
b
. 那么,所谓的激活对象 (在ES3中)或词汇环境记录 (ES5)将与变量名称
b
重叠。 So anytime a JS engine resolves b
it'll stop at the first occurence, which is in its own Scope. 因此,只要JS引擎解析
b
它就会在第一次出现时停止,这是在它自己的Scope中。
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