javascript 将函数中的局部变量传递出去成为全局变量
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Passing local variables from a function out to become global variables
提问by Peter
I've spent the last two hours trying to figure out how to do this but nothing is working. Here is a short sample of some of my code. I want to get arrtime and several other similar variables out of the function so I can use them globally. Any ideas? Nothing too complicated please, I'm no expert (obviously).
我花了最后两个小时试图弄清楚如何做到这一点，但没有任何效果。这是我的一些代码的简短示例。我想从函数中获取 arrtime 和其他几个类似的变量，以便我可以全局使用它们。有任何想法吗？请不要太复杂，我不是专家（显然）。
function showTest(str) {
........
var arrayvals = JSON.parse(xmlhttp.responseText);
var arrtime= (arrayvals[0]);
}
var testvar=arrtime;
document.getElementById("testing").innerHTML=testvar;
回答by J0HN
The clean way to do this is using js-object notation:
干净的方法是使用 js-object 表示法：
function showTest(str) {
//other code
return {arr: arrayvals, tm: arrtime};
}
var func_result = showTest("blah-blah");
var testvar =func_result.tm;
var testvar2=func_result.arr;
But it's generally a bad idea to have global vars. Why do you need it?
但是拥有全局变量通常是一个坏主意。你为什么需要它？
Updatesample code with globalobject
使用global对象更新示例代码
globals = {};
function q(){
globals['a'] = 123;
globals[123] = 'qweqwe';
}
function w(){
alert(globals.a);
//alert(globals.123); //will not work
alert(globals[123]); //that's OK.
}
q();
w();
回答by Thilo
You can declare the variables outside of the function.
您可以在函数之外声明变量。
var arrtime, arrayvals;
function showTest(str) {
arrayvals = JSON.parse(xmlhttp.responseText);
arrtime= (arrayvals[0]);
}
var testvar=arrtime;
alert (testvar);
回答by Joseph Marikle
var testvar;
function showTest(str) {
........
var arrayvals = JSON.parse(xmlhttp.responseText);
var arrtime= (arrayvals[0]);
testvar = arrtime;
}
alert (testvar);
The global is to be declared outside of the score of the function but assigned inside the scope of the function.
global 将在函数的分数之外声明，但在函数的范围内分配。
回答by Van Coding
You simply have to omit varwhich indicates a variable that is only accessible from the function scope.
您只需省略varwhich 表示只能从函数范围访问的变量。
