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）的注册码。I usedmaxlengthto 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：/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'!");elsealert("The string 'Hello World' does not contain the substring 'orl'!");
Here is an example: /oliverni/cb8xw/这是一个示例： http : ///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 findstring1.test(regex); // => truestring2.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" ); }
