这处代码为什么要写成自执行函数

Question

https://segmentfault.com/a/11...我放到了codepen这篇文章中，对Validator.prototype.add方法中一处地方不理解为什么要放到自执行函数中。for(var i = 0, rule; rule = rules[i++];) {             (function(rule) {                var strategyAry = rule.strategy.split(':');                var errorMsg = rule.errorMsg;                self.cache.push(function() {                 var strategy = strategyAry.shift();                 strategyAry.unshift(dom.value);                 strategyAry.push(errorMsg);                 return strategies[strategy].apply(dom, strategyAry);                })             })(rule)   }如果去掉外层的匿名函数就不行。 有什么区别吗？    for(var i = 0, rule; rule = rules[i++];) {        var strategyAry = rule.strategy.split(':');        var errorMsg = rule.errorMsg;        self.cache.push(function() {         var strategy = strategyAry.shift();         strategyAry.unshift(dom.value);         strategyAry.push(errorMsg);         return strategies[strategy].apply(dom, strategyAry);        })     }