js indexOf()和for循环的执行效率那个更高

在js中供给了indexOf（）函数以获取某个字符在字符串中的index，可以经由过程它也断定某个字符或字符串是否存在。

但同时在js中for轮回也可以实现同样的结果（断定字符是否存在）。那么到底用哪个才好呢？

于是写了两个函数来斗劲：

View Code

 1   <script type="text/javascript">
 2         function getValue（） {
 3 
 4             var str = "abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij"
 5             var specialWord = new Array（""""， "\\"， "<"， ">"， "％"， "？"， "/"， "+"， "＠"， "&"， "＃"， "￥"， "……"， "^"， "~"， "!"， "‘"， "’"， "！"， "￥"）; //可以持续添加特别字符 此 /  字符也不成输入 输出时会破损JSON格局
 6             for （var specialWordItem = 0; specialWordItem < specialWord.length; specialWordItem++） {
 7                 var specialIndex = str.indexOf（specialWord[specialWordItem]）;
 8                 if （specialIndex != （-1）） {
 9                     return false;
10                 }
11             }
12             return true;
13         }
14 
15         function getReValue（） {
16 
17             var str = "abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij"
18             var specialWord = new Array（""""， "\\"， "<"， ">"， "％"， "？"， "/"， "+"， "＠"， "&"， "＃"， "￥"， "……"， "^"， "~"， "!"， "‘"， "’"， "！"， "￥"）; //可以持续添加特别字符 此 /  字符也不成输入 输出时会破损JSON格局
19             for （var specialWordItem = 0; specialWordItem < specialWord.length; specialWordItem++） {
20                 for （var j = 0; j < str.length; j++） {
21                     if （specialWord[specialWordItem] == str.charAt（j）） {
22                         return false;
23                     }
24                 }
25             }
26             return true;
27         }
28 
29         function bothFunction（） {
30             getValue（）;
31             getReValue（）;
32         }
33         
34     </script>

str字符串是1000个字符。断定str中是否存在specialWord中的特别字符。机能测试成果如下图所示：

如今可以很明显地看到用indexOf（）机能要好很多。

当然getValue（）还可以持续优化

View Code

 function getValue（str， specialWord） {

            if （（typeof str == "string"） && （specialWord instanceof Array）） {
                var specialIndex = -1，
                    specialWordLength = specialWord.length;

                for （var specialWordItem = specialWordLength - 1; specialWordItem >= 0; specialWordItem--） {
                    specialIndex = str.indexOf（specialWord[specialWordItem]）;
                    if （specialIndex > -1） {
                        return false;
                    }
                }
            }
            return true;
        }