javascript - 如何在JavaScript中声明全局变量？(How to declare a global variable in JavaScript?)

Question

如何在JavaScript中声明全局变量？

  ask by Dancer translate from so

Answer 1

If you have to generate global variables in production code (which should be avoided) always declare them explicitly :

(如果必须在生产代码中生成全局变量（应该避免），请始终 明确声明它们：)

window.globalVar = "This is global!";

While it is possible to define a global variable by just omitting var (assuming there is no local variable of the same name), doing so generates an implicit global, which is a bad thing to do and would generate an error in strict mode .

(虽然可以通过省略var来定义全局变量（假设没有相同名称的局部变量），但这样做会生成一个隐式全局，这是一件坏事，并且会在严格模式下生成错误。)