一个 JavaScript 函数

发布于 2024-11-15 16:47:16 字数 148 浏览 3 评论 0原文

请解释以下在 javascript 函数中编写函数的方法：

(function (){
 // some code 
})()

我知道由于尾部大括号“ () ”，该函数将立即执行，但是将函数括在大括号中意味着什么？

原文

Please explain the following way of writing a function in javascript functions :

(function (){
 // some code 
})()

I understand the fact that because of the trailing braces " () ", the function will execute immediately but but what does enclosing the function in the braces mean?

分享到QQ

分享到微博

如果你对这篇内容有疑问，欢迎到本站社区发帖提问参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。

发布评论

需要登录才能够评论，你可以免费注册一个本站的账号。

扛起拖把扫天下 2024-11-22 16:47:16

你的语法不正确。编辑：已修复。

看一下您只想调用一次且仅一次的普通函数定义：

function add(x,y) {
   var z = x + y; 
   // do something with z
}

add(2,3);

您可以减少此代码，以便立即执行它，无需将其命名为 add：

(function(x ,y) {
   var z = x + y; 
   // do something with z
})(2,3)

注意我们是如何包围的该函数带有一组括号，使其成为可调用表达式。此模式通常用于创建某些变量的闭包（捕获其状态），例如：

jQuery.noConflict(); //Disables the use of $ in the global scope
(function($) {

   //Safely use $ inside this function
   $('.link').click(function(e) {
      //etc
   });

})(jQuery);

Your syntax is incorrect. Edit: fixed.

Look at a normal function definition that you want to call once and only once:

function add(x,y) {
   var z = x + y; 
   // do something with z
}

add(2,3);

You could reduce this code so that you execute it straight away, there is no need to name it add:

(function(x ,y) {
   var z = x + y; 
   // do something with z
})(2,3)

Note how we have surrounded the function with a set of parenthesis to make it a callable expression. This pattern is often used to create a closure (capture the state of) certain variables, for example:

jQuery.noConflict(); //Disables the use of $ in the global scope
(function($) {

   //Safely use $ inside this function
   $('.link').click(function(e) {
      //etc
   });

})(jQuery);

回复收藏 0 原文

七堇年 2024-11-22 16:47:16

正如 RobG 指出的，这是您原始问题中唯一有效的陈述选择。

(function (){
 // some code 
}())

它在解析后立即执行，并提供了一种将函数内的代码从其余代码中排除的方法。这称为闭包（请参阅MDN 上的闭包）并且可以帮助解决脚本中的内存泄漏。

As RobG pointed out, this is the only valid statement choice in your original question.

(function (){
 // some code 
}())

This is executed right after it is parsed, and provides a way to out-scope the code inside the function from the rest of your code. This is called a closure (see Closures on MDN) and may help with memory leaks in your scripts.

回复收藏 0 原文