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Closure: The Definitive Guide 
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注意看变量reg的位置变化
```
function filtrate2() {
var newArr = [], reg = /^\s*$/g,
str = "baidu,google, , ,baidu,google,bg";
arr = str.split(',');
for (var i = 0; i < arr.length; i++) {
//var reg = /^\s*$/g;
if (!reg.test(arr[i])) {
newArr.push(arr[i]);
}
}
return newArr;
}
//执行结果 ["baidu", "google", " ", "baidu", "google", "bg"]
function filtrate2() {
var newArr = [], reg = /^\s*$/g,
str = "baidu,google, , ,baidu,google,bg";
arr = str.split(',');
for (var i = 0; i < arr.length; i++) {
var reg = /^\s*$/g;
if (!reg.test(arr[i])) {
newArr.push(arr[i]);
}
}
return newArr;
}
//执行结果 ["baidu", "google", "baidu", "google", "bg"]
```
我觉得是和 js 的作用域有关，但又说不清楚，请各位赐教。
```
function filtrate2() {
var newArr = [], reg = /^\s*$/g,
str = "baidu,google, , ,baidu,google,bg";
arr = str.split(',');
for (var i = 0; i < arr.length; i++) {
//var reg = /^\s*$/g;
if (!reg.test(arr[i])) {
newArr.push(arr[i]);
}
}
return newArr;
}
//执行结果 ["baidu", "google", " ", "baidu", "google", "bg"]
function filtrate2() {
var newArr = [], reg = /^\s*$/g,
str = "baidu,google, , ,baidu,google,bg";
arr = str.split(',');
for (var i = 0; i < arr.length; i++) {
var reg = /^\s*$/g;
if (!reg.test(arr[i])) {
newArr.push(arr[i]);
}
}
return newArr;
}
//执行结果 ["baidu", "google", "baidu", "google", "bg"]
```
我觉得是和 js 的作用域有关，但又说不清楚，请各位赐教。
 | 1 Niris Apr 20, 2016  1 |
 | 3 w88975 Apr 20, 2016 1 function filtrate2() { var newArr = [], reg = /^\s*$/g, str = "baidu,google, , ,baidu,google,bg"; arr = str.split(','); for (var i = 0; i < arr.length; i++) { if (!reg.test(arr[i])) { newArr.push(arr[i]); } reg.lastIndex = 0; } return newArr; } |
 | 4 Arrowing Apr 20, 2016 arr = str.spit(','); 导致的，这里的 arr 是全局对象下的 arr 前面一行最后面是分号，不是逗号！！！！ |
| 5 Arrowing Apr 20, 2016 啊，看错题了，忽略上一条 0.0 |
| 6 Arrowing Apr 20, 2016 1 1 楼说得对，是因为 lastIndex 被改变了，重新定义的 reg 对象又初始化了 lastIndex |
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