这是经常重复的如何在闭包问题中使用循环变量。

This is the very frequently repeated "how do I use a loop variable in a closure" problem.

规范的解决方案是调用一个函数，该函数返回一个绑定到循环变量当前值的函数：

The canonical solution is to call a function which returns a function that's bound to the current value of the loop variable:

var strings = [ "hello", "world" ];
var delay = 1000;
for(var i=0;i<strings.length;i++) {
    setTimeout(
        (function(s) {
            return function() {
                alert(s);
            }
        })(strings[i]), delay);
    delay += 1000;
}

外部定义 function（s）{.. 。} 创建一个新范围，其中 s 绑定到所提供参数的当前值 - 即 strings [i] - 内部范围可用的地方。

The outer definition function(s) { ... } creates a new scope where s is bound to the current value of the supplied parameter - i.e. strings[i] - where it's available to the inner scope.