Java语言函数while循环内的冒号 [英] Colon within a Javascript function while loop

问题描述

我正在浏览一些HTML5 Javascript演示，并且遇到了我以前从未在语法中见过的东西.查看run函数，并注意在 while循环中如何创建 search 对象符号.感兴趣的行包括15和18.有人可以解释这种语法吗?

  function run(){var n = 1;搜索:while(运行中){n + = 1;对于(var i = 2; i< = Math.sqrt(n); i + = 1)如果(n％i == 0)继续搜索；//找到一个素数！postMessage(n);}} 

(从此处获取的代码； http://html5demos.com/js/cruncher.js)

解决方案

这不是对象(文字)符号，它是http://html5demos.com/js/cruncher.js)

解决方案

This is not object (literal) notation, it is defining a label.

A label can be used to give a looping construct a name. The benefits of doing this is that you can create more powerful breaks; or continues; by referencing outer loops (by their labels).

Note that how the structure of the program you referenced is a:

search: while () {
   for (;;;) {

   }
}

... and the author is using continue search; inside the for loop to continue the execution of the while loop.

As for what's happening on line 18, if (n % i == 0) is using the modulo (%) operator to get the remainder between dividing n / i, and checking whether it's 0.

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