在函数外访问 JavaScript 函数变量
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Accessing JavaScript function variables outside of the function
提问by mwilson
I apoligize for my newbness but I'm not clearly understanding how to access variables within a function outside of the function. I understand that you need to pass them some how but I'm not 100% sure on the whys and hows.
我为我的新手道歉，但我不清楚如何在函数外访问函数内的变量。我知道您需要向他们传递一些方法，但我不能 100% 确定原因和方法。
Taking the below code for example, I want to use the var degreethroughout the code outside of the function. How do I do it?
以下面的代码为例，我想var degree在函数之外的整个代码中使用。我该怎么做？
function DegreeToMil()
{
//Degree's to Mils: 1 Degree = 17.777778 Mils
var degree = 10;
var mils = degree * 17.777778;
return mils;
}
回答by Pandacoder
It is actually fairly simple, just define it outside of the function.
其实很简单，在函数外定义就行了。
Edit: Updated with an example, and comments explaining what was done and how it works.
编辑：更新了一个例子，并解释了做了什么以及它是如何工作的评论。
DegreesToMils.degrees = 10; /* This is a static variable declaration to make sure it isn't undefined
* See note 1 below */
function DegreesToMils(degrees) {
if (degrees !== undefined) {
DegreesToMils.degrees = degrees; /* If the parameter is defined,
* it will update the static variable */
}
var milsPerDegree = 17.777778; /* This is a variable created and accessible within the function */
return DegreesToMils.degrees * milsPerDegree; /* The function will return 177.77778 */
}
console.log(DegreesToMils.degrees); /* Prints 10, Note 1: This would be undefined if
* not declared before the first call to DegreesToMils() with a
* defined parameter
*/
console.log(DegreesToMils(10)); /* Prints 177.77778 */
console.log(DegreesToMils(9)); /* Prints 160.00000200000002, Sets DegreesToMils.degrees to 9 */
console.log(DegreesToMils.degrees); /* Prints 9 */
回答by mwilson
function DegreeToMil()
{
//Degree's to Mils: 1 Degree = 17.777778 Mils
var degree = 10;
var mils = degree * 17.777778;
var result = [degree, mils]; // it's an array
return result;
}
// use it like this
var myResult = DegreeToMil();
console.log(myResult[0]); // degree
console.log(myResult[1]); // mils
