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如何判断一个字符串在JavaScript中是否包含某个字符？

程序员文章站 2023-12-21 16:59:04
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本文翻译自：How to tell if a string contains a certain character in JavaScript?

I have a page with a textbox where a user is supposed to enter a 24 character (letters and numbers, case insensitive) registration code. 我有一个带有文本框的页面，用户应在其中输入24个字符（字母和数字，不区分大小写）的***。 I used maxlength to limit the user to entering 24 characters. 我使用maxlength将用户限制为输入24个字符。

The registration codes are typically given as groups of characters separated by dashes, but I would like for the user to enter the codes without the dashes. 注册代码通常以破折号分隔的字符组形式给出，但是我希望用户输入不带破折号的代码。

How can I write my JavaScript code without jQuery to check that a given string that the user inputs does not contain dashes, or better yet, only contains alphanumeric characters? 如何在没有jQuery的情况下编写我的JavaScript代码，以检查用户输入的给定字符串不包含破折号，或者更好的是，仅包含字母数字字符？

#1楼

参考：https://stackoom.com/question/IeD7/如何判断一个字符串在JavaScript中是否包含某个字符

#2楼

检查字符串（单词/句子...）是否包含特定的单词/字符

if ( "write something here".indexOf("write som") > -1 )  { alert( "found it" );  }

#3楼

Working perfectly.This exmple will help alot. 完美的工作。这个例子会很有帮助。 

<script>    
    function check()
    {
       var val = frm1.uname.value;
       //alert(val);
       if (val.indexOf("@") > 0)
       {
          alert ("email");
          document.getElementById('isEmail1').value = true;
          //alert( document.getElementById('isEmail1').value);
       }else {
          alert("usernam");
          document.getElementById('isEmail1').value = false;
          //alert( document.getElementById('isEmail1').value);
       }
    }
</script>

<body>
    <h1>My form </h1>
    <form action="v1.0/user/login" method="post" id = "frm1">
        <p>
            UserName : <input type="text" id = "uname" name="username" />
        </p>
        <p>
            Password : <input type="text" name="password" />
        </p>
        <p>
            <input type="hidden" class="email" id = "isEmail1" name = "isEmail"/>
        </p>
        <input type="submit" id = "submit" value="Add User" onclick="return check();"/>
    </form>
</body>

#4楼

Try this: 尝试这个： 

if ('Hello, World!'.indexOf('orl') !== -1)
    alert("The string 'Hello World' contains the substring 'orl'!");
else
    alert("The string 'Hello World' does not contain the substring 'orl'!");

Here is an example: http://jsfiddle.net/oliverni/cb8xw/ 这是一个示例： http : //jsfiddle.net/oliverni/cb8xw/

#5楼

You're all thinking too hard. 你们都在想 Just use a simple Regular Expression, it's your best friend. 只需使用一个简单的正则表达式，它就是您最好的朋友。 

var string1 = "Hi Stack Overflow. I like to eat pizza."
var string2 = "Damn, I fail."

var regex = /(pizza)/g // Insert whatever phrase or character you want to find

string1.test(regex); // => true
string2.test(regex); // => false

Learn Regex in 5 minutes? 在5分钟内学习正则表达式？

#6楼

 var inputString = "this is home"; var findme = "home"; if ( inputString.indexOf(findme) > -1 ) { alert( "found it" ); } else { alert( "not found" ); }

相关标签： javascript string

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