Validations for Password and First name using JavaScript

Question

Validations for Password and First name using JavaScript

6.4k Views Asked by sundeep At 17 May 2025 at 13:36

I am doing form validations and the requirement is 1.Email : Email must be a valid Email ID. 2.Password : Must be eight characters long. Only number(0-9) and letters(A-Z,a-z) are allowed. 3.FirstName : Must not contain any numbers(0-9). 4.LastName : Must not contain any numbers (0-9). I did for email Address and I am struck with the password and FirstName validations.. Can Anyone help me in this Thanks in Advance.

    <form>
            <label for="">First Name</label>
            <input type="text" id="fname"><br>
            <label for="">Last Name</label>
            <input type="text" id="lname"><br>
            <label for="">Email</label>
            <input type="text" id="email"><br>
            <label for="">Password</label>
            <input type="text" id="password"><br>
           <button type="button" onclick="claim()">Claim Your Free Trail</button>
           <p>You Are Agreeing to Our <a href="#">Terms & Condition</a></p>
        </form>

        <script>
            function claim(){
                var obj ={
                    fname:"",
                    lname:"",
                    email:"",
                    password:""
                }

                for(a in obj){
                    obj[a]=document.getElementById(a).value
                }
                if(obj.email.match(/@/) != null){

                }else{
                    alert("Please enter Valid Email Address")
                }
                console.log(obj)
            }
        </script>
    </body>

Original Q&A

There are 3 best solutions below

Muhammed Sabeeh On 16 October 2019 at 02:02

Just go about it using regular expressions. https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

Code Maniac On 16 October 2019 at 02:17

You can use pattern and inbuilt validation of HTML form

[^\d]+ - To allow only characters except digits
[\dA-Za-z]{8,} - To make sure only digits, and alphabets are allowed and atleast 8 characters

<body>
  <form validate>
    <label for="">First Name</label>
    <input type="text" id="fname" pattern="[^\d]+" required><br>
    <label for="">Last Name</label>
    <input type="text" id="lname"><br>
    <label for="">Email</label>
    <input type="email" id="email" required><br>
    <label for="">Password</label>
    <input type="password" id="password" pattern="[\dA-Za-z]{8,}" required><br>
    <button type="submit">Claim Your Free Trail</button>
    <p>You Are Agreeing to Our <a href="#">Terms & Condition</a></p>
  </form>
</body>

**samhodev** · Accepted Answer

Password validation

We use the following regular expression to ensure the password contains only letters and numbers:

/[^A-Za-z0-9]+/g

[^] : Matches anything NOT in the set
A-Z : Characters in the range "A" to "Z"
a-Z: Characters in the range "a" to "z"
0-9: Characters in the range "0" to "9"
g: Global flag, allowing inerative search

So if the password contains non-letters and numbers, the regular expression return true.

And the whole password validation function as follow:

function isValidPassword(password) {
    if (
        typeof password !== "string" ||
        password.length !== 8 ||
        /[^A-Za-z0-9]+/g.test(password)
    ) 
        return false;
    return true;
}

Firstname validation

We use the following regular expression to check if the password contains any numbers:

/[0-9]+/g

[] : Matches anything IN the set
0-9: Characters in the range "0" to "9"
g: Global flag, allowing inerative search

And the whole first name validation function as follow:

function isValidFirstname(firstname) {
    if (
        typeof firstname !== "string" ||
        /[0-9]+/g.test(firstname)
    ) {
        return false; 
    }
    return true;
}

Validations for Password and First name using JavaScript

There are 3 best solutions below

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