javascript - Javascript 验证中的正则表达式

我对 javascript 很陌生，一直在尝试正则表达式。我正在尝试创建一个简单的密码/用户名验证表单。我相信我的正则表达式是错误的，并且我在某个地方搞乱了我的语法，因为这不会运行。谁能告诉我我做错了什么？谢谢。

这是我的代码:

 <html>

 <head>

 <title>Username/Password Validation</title>

 <script type="text/javascript">

 function check(username, password, passwordAgain)
 {
// at least one number, one lowercase and one uppercase letter 
// at least six - ten characters that are letters, numbers or the underscore 
var pwd = /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])\w{6,10}$/;

// at least six - ten characters that are letters, numbers or the underscore 
//the first character CANNOT start with a digit
var user = /^!=.*\d\w{6,10}$/;

if (pwd.test(password)) && (user.test(username)) && (password == passwordAgain)
{
alert("Passed Validation");
}
else if (password != passwordAgain)
{
alert(Your passswords don't match.");
}
else if !(pwd.test(password)) && !(user.test(username))
{
alert(username + password + " Your password and username are not valid.");
}
else if !(pwd.test(password)) && (user.test(username))
{
alert(password + " This password is not valid.");
}
else
{
alert(username +" This username is not valid.");
}


 </script>
 </head>

 <body>

 <form>

 <h3> Username-Password Validation </h3>

<ul>
<li> The username must be between 6 and 10 characters long. </li>
<li> The username must contain only letters and digits. </li>
<li> The username cannot begin with a digit. </li>
<li> The password and the repeat password must match. </li>
<li> The password must be between 6 and 10 characters. </li>
<li> The password must contain only letters and digits. </li>
<li> The password must have at least one lower case letter,<br /> at
 least one upper case letter, and at least one digit. </li>
</ul>


Username: <input type = 'text' id = 'username' /> <br />

Password: <input type = 'text' id = 'password' /> <br />

Reenter Password: <input type = 'text' id = 'passwordAgain' /> <br/> 

<p>

<input type ='button' onclick='check(username, password, passwordAgain )' value='Submit' />

<input type ='reset' value='Clear' /> 

</p>

</form>

</body>

</html>

*编辑***

<html>
<head>
 <title>Username/Password Validation</title>

 <script type="text/javascript">
    function check(username, password, passwordAgain){
        //List of possible error messages
        var errorList = '';

        // at least six - ten characters that are letters, numbers or the underscore
        var sixtotencharacters = /\w{6,10}$/;

        // at least one number, one lowercase and one uppercase letter 
        var oneofeach = /^(?=.*\d)(?=.*[a-z])(?=.*[A-Z])/;

        //first character does not start with digit
        var firstDigit = /^!=.*\d/;

        //Begin validation

        if (sixtotencharacters.test(password) && sixtotencharacters.test(username)  && oneofeach.test(password) && firstDigit.test(username) && password == passwordAgain)
           {
            alert("Passed Validation");
    }
        else
        {
         if (password != passwordAgain){
            errorlist = 'Your passswords don\'t match. ';
        }if (!sixtotencharacters.test(username)){
            errorlist = errorlist + 'Username needs to be six to ten characters. ';
        }if (!sixtotencharacters.test(password)){
            errorlist = errorlist + 'Password needs to be six to ten characters. ';
        }if (!oneofeach.test(password)){
            errorlist = errorlist + 'You need to have at least one number, one lowercase and one uppercase letter. ';
        }if (!firstDigit.test(username)){
            errorlist = errorlist + 'First character of username can\'t be a digit. ';
        }
    alert(errorlist);

    }
   </script>
</head>

<body>

<form>

<h3> Username-Password Validation </h3>

<ul>
<li> The username must be between 6 and 10 characters long. </li>
<li> The username must contain only letters and digits. </li>
<li> The username cannot begin with a digit. </li>
<li> The password and the repeat password must match. </li>
<li> The password must be between 6 and 10 characters. </li>
<li> The password must contain only letters and digits. </li>
<li> The password must have at least one lower case letter,<br /> at
 least one upper case letter, and at least one digit. </li>
</ul>


Username: <input type = 'text' id = 'username' /> <br />

Password: <input type = 'text' id = 'password' /> <br />

Reenter Password: <input type = 'text' id = 'passwordAgain' /> <br/> 

<p>

<input type ='button' onclick='check(username, password, passwordAgain )' value='Submit' />

<input type ='reset' value='Clear' /> 

</p>

</form>

</body>

</html>

**这是最新的更新，使 Jason 的建议更进一步< em>* 用户名/密码验证

  <script>
    window.onload = check() {
        document.getElementById('btnSubmit').addEventListener('click', check() {
            var errors = [];
            var username = document.getElementById('username').value;
            var password = document.getElementById('password').value;
    var passwordAgain = document.getElementById('passwordAgain').value;
            var errorList = document.getElementById("errors");

            errorList.innerHTML = '';

    if (password != passwordAgain) { errors.push("Your passwords do not match") }

            var hasNumber = password.match(/\d+/);

            if (hasNumber == null) { errors.push("You did not include a number in your password") }

            var hasUpper = password.match(/[A-Z]+/);

            if (hasUpper == null) { errors.push("You did not include an Uppercase Letter in your password") }

            var hasLower = password.match(/[a-z]+/);

            if (hasLower == null) { errors.push("You did not include an Lowercase Letter in your password") }

    var hasAtleast6lessThan10password = password.length < 6 || password.length > 10; 

    if (hasAtleast6lessThan10password) { errors.push("Your password must be at least 6 characters long and cannot be more than 10") } 

            var hasAtleast6lessThan10username = username.length < 6 || username.length > 10;

            if (hasAtleast6lessThan10username) { errors.push("Your username must be at least 6 characters long and cannot be more than 10") } 

            var firstCharacterNotDigit = username.match(/^[^\d]/);

            if (firstCharacterNotDigit == null) { errors.push("Your username may not begin with a number") }  

            if (errors.length > 0) {

                for (var i = 0; i < errors.length; i++) {
                    var errorElem = document.createElement("li");
                    errorElem.innerHTML = errors[i];

                    errorList.appendChild(errorElem);
                }
            }

        });
    };
</script>


</head>

<body>

<form>

<h3> Username-Password Validation </h3>

<ul>
<li> The username must be between 6 and 10 characters long. </li>
<li> The username must contain only letters and digits. </li>
<li> The username cannot begin with a digit. </li>
<li> The password and the repeat password must match. </li>
<li> The password must be between 6 and 10 characters. </li>
<li> The password must contain only letters and digits. </li>
<li> The password must have at least one lower case letter,<br /> at
 least one upper case letter, and at least one digit. </li>
</ul>


Username: <input type = 'text' id = 'username' size="10" /> <br />

Password: <input type = 'text' id = 'password' size="10"/> <br />

Reenter Password: <input type = 'text' id = 'passwordAgain' size="10" /> <br/> 

<p>

<input type ='button' onclick='check()' value='Submit' />

<input type ='reset' value='Clear' /> 

</p>

</form>

</body>

</html>

最佳答案

在我看来，使用单个正则表达式来验证密码是否符合所有规则是一个错误，原因有两个。

future 改变规则将是一项艰巨的任务
您无法告诉最终用户他们违反了哪一部分。如果他们忘记添加数字，您不能说“您需要添加至少一个数字”。相反，您只能说验证失败“密码无效”。

我建议为每个规则使用一个单独的、简单的正则表达式，然后运行它们，收集一系列违反规则的错误，然后立即向用户提供所有错误。这将带来更好的用户体验，并使您的验证工作变得更加轻松。

更新:这是我的想法:

<!DOCTYPE html> 
<html>
<head>
<meta charset="UTF-8">
<title>Password Checking with JavaScript</title>
    <script>
        window.onload = function() {
            document.getElementById('btnSubmit').addEventListener('click', function() {
                var errors = [];
                var username = document.getElementById('username').value;
                var password = document.getElementById('password').value;
                var errorList = document.getElementById("errors");

                errorList.innerHTML = '';

                var hasNumber = password.match(/\d+/);

                if (hasNumber == null) { errors.push("You did not include a number in your password") }

                var hasUpper = password.match(/[A-Z]+/);

                if (hasUpper == null) { errors.push("You did not include an Uppercase Letter in your password") }

                var hasLower = password.match(/[a-z]+/);

                if (hasLower == null) { errors.push("You did not include an Lowercase Letter in your password") }

                var hasAtleast8lessThan10 = username.length < 6 || username.length > 10;

                if (hasAtleast8lessThan10) { errors.push("You username must be at least 8 characters long and cannot be more than 10") }  


                var fisrtCharacterNotDigit = username.match(/^[^\d]/);

                if (fisrtCharacterNotDigit == null) { errors.push("Your username may not begin with a number") }  

                if (errors.length > 0) {

                    for (var i = 0; i < errors.length; i++) {
                        var errorElem = document.createElement("li");
                        errorElem.innerHTML = errors[i];

                        errorList.appendChild(errorElem);
                    }
                }

            });
        };
    </script>
</head> 
<body> 
    <ul id="errors"></ul>
    <input type="textbox" name="username" id="username" size="3">
    <input type="textbox" name="password" id="password" size="3">
    <button id="btnSubmit" >Check Password</button>
</body>
</html>

更新:我正在更新我的答案，以便为用户提供满足其需求的附加解决方案。

我对上面的第三次更新脚本所做的更改是:

window.onload = check() {... 行不正确。如果没有关键字“function”，您就不会给它一个可以使用的函数。另外，由于您使用内联单击事件触发该函数，因此不需要执行此加载，也不需要下一行的单击事件监听器，因此我也将其删除。
行:

var errorList = document.getElementById("错误");

errorList.innerHTML = '';

导致语法错误，因为 div“错误”不再存在，因此不需要它们。

我更新了最后一部分以抛出警报消息，而不是将消息整齐地显示在表单上方。不知道为什么你会想要这个，但是好吧。你可能至少想进去把它们弄得更整洁。

希望这有帮助

<!DOCTYPE html > 
<html>
    <head>
        <meta charset="UTF-8">
        <title>Password Checking with JavaScript</title>

        <script>
            function check() {
                var errors = [];
                var username = document.getElementById('username').value;
                var password = document.getElementById('password').value;
                var passwordAgain = document.getElementById('passwordAgain').value;

                if (password != passwordAgain) { errors.push("Your passwords do not match") }

                var hasNumber = password.match(/\d+/);

                if (hasNumber == null) { errors.push("You did not include a number in your password") }

                var hasUpper = password.match(/[A-Z]+/);

                if (hasUpper == null) { errors.push("You did not include an Uppercase Letter in your password") }

                var hasLower = password.match(/[a-z]+/);

                if (hasLower == null) { errors.push("You did not include an Lowercase Letter in your password") }

                var hasAtleast6lessThan10password = password.length < 6 || password.length > 10; 

                if (hasAtleast6lessThan10password) { errors.push("Your password must be at least 6 characters long and cannot be more than 10") } 

                var hasAtleast6lessThan10username = username.length < 6 || username.length > 10;

                if (hasAtleast6lessThan10username) { errors.push("Your username must be at least 6 characters long and cannot be more than 10") } 

                var firstCharacterNotDigit = username.match(/^[^\d]/);

                if (firstCharacterNotDigit == null) { errors.push("Your username may not begin with a number") }  

                if (errors.length > 0) {
                    alert(errors.join('\r\r'));
                }
            };
        </script>


    </head>

    <body>

            <form>

            <h3> Username-Password Validation </h3>

            <ul>
            <li> The username must be between 6 and 10 characters long. </li>
            <li> The username must contain only letters and digits. </li>
            <li> The username cannot begin with a digit. </li>
            <li> The password and the repeat password must match. </li>
            <li> The password must be between 6 and 10 characters. </li>
            <li> The password must contain only letters and digits. </li>
            <li> The password must have at least one lower case letter,<br /> at
             least one upper case letter, and at least one digit. </li>
            </ul>


            Username: <input type = 'text' id = 'username' size="10" /> <br />

            Password: <input type = 'text' id = 'password' size="10"/> <br />

            Reenter Password: <input type = 'text' id = 'passwordAgain' size="10" /> <br/> 

            <p>

            <input type ='button' onclick='check()' value='Submit' />

            <input type ='reset' value='Clear' /> 

            </p>

            </form>

    </body>
</html>

关于javascript - Javascript 验证中的正则表达式，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/7697836/

javascript - Javascript 验证中的正则表达式

更新:我正在更新我的答案，以便为用户提供满足其需求的附加解决方案。

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