js switch(true){case"fetch"inglobalThis:// 使用 fetch 获取资源。break;case"XMLHttpRequest"inglobalThis:// 使用 XMLHttpRequest 获取资源。break;default:// 使用自定义 AJAX 逻辑获取资源break;} switch (true)模式作为if...else结构的一种替代方案,在希望利用穿透行为时特别有用。
jsCopy to Clipboard let myFunc; if (num === 0) { myFunc = function (theObject) { theObject.make = "Toyota"; }; } 除了上述的定义函数方法外,你也可以在运行时用 Function 构造函数从一个字符串创建一个函数,很像 eval() 函数。 当一个函数是一个对象的属性时,称之为方法。了解更多关于对象...
switch 语句和 export 语句页面. 例子 在switch语句中使用default In the following example, if expr evaluates to "Bananas" or "Apples", the program matches the values with either the case "Bananas" or "Apples" and executes the corresponding statement. The default keyword will help in any other ...
理解JavaScript在不同环境下使用不同的事件模型很重要——从Web api到其他领域,如浏览器WebExtensions(用于开发跨浏览器的插件)和Node.js(服务器端JavaScript)。 The event model in JavaScript for web pages differs from the event model for JavaScript as it is used in other environments. For example, Node...
You should not use an object literal at the beginning of a statement. This will lead to an error or not behave as you expect, because the { will be interpreted as the beginning of a block. The following is an example of an object literal. The first element of the car object defines ...
subset of those operating systems, then the support statement should set"partial_implementation": true. For example, if a browser supports both Windows and Linux, but only implements a feature on Windows, then a support statement for that feature should set"partial_implementation": true(and a...
https://github.com/w3c/mdn-spec-links/blob/master/.browser-compat-data-process.js#L256 I am not enthusiastic about imposing the burden on all other downstream consumers of (re)writing that same kind of code. So to keep things as clear as possible and to avoid the need for all downstream...
jsCopy to Clipboard let myFunc; if (num === 0) { myFunc = function (theObject) { theObject.make = "Toyota"; }; } 除了上述的定义函数方法外,你也可以在运行时用 Function 构造函数从一个字符串创建一个函数,很像 eval() 函数。 当一个函数是一个对象的属性时,称之为方法。了解更多关于对象...
constresult=/(a+)(b+)(c+)/.exec("aaabcc");var[,a,b,c]=result;console.log(a,b,c);// "aaa" "b" "cc" 有关更多信息,请参阅解构赋值。 Specification ECMAScript Language Specification #sec-variable-statement Report problems with this compatibility data on GitHub ...
switch语句对一个表达式求值,将结果与 case 子语句比较,如果匹配,则从 case 处的语句向下执行。 375 throw JavaScript, Statement, 流程控制 throw 语句用来抛出用户自定义异常。当前函数的执行将会被中止(throw之后的语句将会得不到执行),接着执行流程会转移到第一个 catch 语句块。如果在调用方函数中没有任何catch...