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  • JavaScript 字符串对象

    JavaScript对象

    1 indexOf()  查找某个字符在字符串中第一次出现的位置,如果没有该字符,则返回-1

     1 <!DOCTYPE html>
     2 <html lang="en">
     3 <head>
     4     <meta charset="UTF-8">
     5     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     6     <title>Document</title>
     7 </head>
     8 <body>
     9     <script>
    10         var s1 = "abcdefg";
    11         //indexOf()  用于查找某个字符在字符串中的索引号,索引号从 0 开始
    12          console.log(s1.indexOf("a"));
    13          //如果该字符串中并不存在该字符,那么返回一个 -1
    14          console.log(s1.indexOf("z"));
    15     </script>
    16 </body>
    17 </html>

    2.根据索引号返回字符串  charAt(index)

    可以用来遍历字符串

    <!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Document</title>
    </head>
    <body>
        <script>
            var s1 = "zhang";
            //charAt(index)  根据索引号返回相应的字符
           for(var i=0;i<s1.length;i++){
               console.log(s1.charAt(i));
               
           }
        </script>
    </body>
    </html>

    3.截取字符串   substr(截取的起始位置,截取几个字符);

     1 <!DOCTYPE html>
     2 <html lang="en">
     3 
     4 <head>
     5     <meta charset="UTF-8">
     6     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     7     <title>Document</title>
     8 </head>
     9 
    10 <body>
    11     <script>
    12         var s1 = "zhangshan";
    13         //截取字符串   substr(截取的起始位置,截取几个字符);
    14         console.log(s1.substr(2, 3));
    15     </script>
    16 </body>
    17 
    18 </html>

    4,替换字符

    replace(要被替换的字符,替换为的字符); //只会替换第一字符

     1 <!DOCTYPE html>
     2 <html lang="en">
     3 
     4 <head>
     5     <meta charset="UTF-8">
     6     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     7     <title>Document</title>
     8 </head>
     9 
    10 <body>
    11     <script>
    12         //replac(被替换的字符,替换为的字符), 但是只能替换第一个字符
    13          var s1 = "zhangshan";
    14         s1 = s1.replace("a","b");
    15         console.log(s1);
    16 
    17         //replace()也可以替换字符串
    18         var s2 = "abcefg"
    19         s2 = s2.replace("abc","ujk");
    20         console.log(s2);
    21         
    22     </script>
    23 </body>
    24 
    25 </html>

    5. 将字符串转换成数组

    split("分隔符")

     1 <!DOCTYPE html>
     2 <html lang="en">
     3 
     4 <head>
     5     <meta charset="UTF-8">
     6     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     7     <title>Document</title>
     8 </head>
     9 
    10 <body>
    11     <script>
    12         
    13          var s1 = "zhang,shan";
    14          s1 = s1.split(",");
    15          console.log(s1);
    16     </script>
    17 </body>
    18 
    19 </html>

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  • 原文地址:https://www.cnblogs.com/zysfx/p/12775725.html
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