javascript createAdder函数功能与使用说明

英文原文
createAdder(x) is a function that returns a function. In JavaScript, functions are first-class objects: they can be passed to other functions as arguments and returned from functions as well. In this case, the function returned is itself a function that takes an argument and adds something to it.

Here"codetitle">复制代码 代码如下:
function createAdder(x) {
return function(y) {
return y + x;
}
}
addThree = createAdder(3);
addFour = createAdder(4);
document.write('10 + 3 is ' + addThree(10) + '<BR>');
document.write('10 + 4 is ' + addFour(10));
document.write('-10 + 4 is ' + addFour(-10));


演示代码:

[Ctrl+A 全选 注:引入外部Js需再刷新一下页面才能执行]