function map(f, a) { const result = new Array(a.length); for (let i = 0; i < a.length; i++) { result[i] = f(a[i]); } return result; } 在以下代码中,该函数接收由函数表达式定义的函数,并对作为第二个参数接收的数组的每个元素执行该函数: jsCopy to Clipboard function map(f,...
Data and tools related to MDN Web Docs (formerly Mozilla Developer Network, formerly Mozilla Developer Center...) - MDN Web Docs
console.log(ary2.next());//Object {value: Array[2], done: false} value:Array[2] ---[0:0,1:1]; console.log(ary2.next());//Object {value: Array[2], done: false} value:Array[2] ---[0:1,1:2]; //可以看出每次执行这个next().都会返回一个该数组的索引和值组成的新的数组,被...
JavaScript 的内存生命周期和垃圾回收。 事件循环 JavaScript 拥有基于“事件循环”的运行时模型。 浏览完整的JavaScript 参考文档。 标准对象 了解Array、Boolean、Date、Error、Function、JSON、Math、Number、Object、RegExp、String、Map、Set、WeakMap、WeakSet等标准内置对象。
MDN Web Docs is an open-source, collaborative project that documents web technologies including CSS, HTML, JavaScript, and Web APIs. Alongside detailed reference documentation, we provide extensive learning resources for students and beginners getting started with web development. MDN's mission MDN's ...
The MDN Web Docs site provides information about Open Web technologies including HTML, CSS, and APIs for both Web sites and progressive web apps.
了解更多并加入 MDN Web Docs 社区。 this Baseline Widely available This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015. Learn more See full compatibility Report feedback 与其他语言相比,函数的 this 关键字在...
MDN Web Docs, previously known as the Mozilla Developer Network, is one of the best documentation sources for web development around. It's a fantastic resource for learning everything from new CSS properties to the latest APIs for Chrome extensions, and now the site has a brand new look and...
MDN Web Docs, previously known as the Mozilla Developer Network, is one of the most popular sources for documentation on web standards. The website is a great resource for everything from Chrome extensions to the latest JavaScript APIs, and earlier this month,Mozilla revealed a paid subscription...
#event-beforeunload HTML #handler-window-onbeforeunload See also BeforeUnloadEventinterface Related events: DOMContentLoaded readystatechange load unload Page Lifecycle APIprovides more useful guidance on handling page lifecycle behavior in your web apps. ...