Form Validation using jQuery

Last Updated : 16 Sep, 2024

Form validation is a process of confirming the relevant information entered by the user in the input field. In this article, we will be validating a simple form that consists of a username, password, and a confirmed password using jQuery.

Below are the approaches for validation of form using jQuery:

Table of Content

Using plain jQuery
Validation using an inbuilt jQuery validation plugin

Using plain jQuery

First, you need to create an index.html file consisting of an HTML form with username, email, password, and confirm password as input fields.
We will use Bootstrap 4 to use Bootstrap's form controls. At the bottom of the <body> tag, include the "app.js" file having jQuery code for form validation.
Create an app.js file that validates the whole form as given below in the code.
In the app.js file, when the document is ready, hide all the error messages.
Perform the validation task for all the input fields such as username, email, password, and confirm password.

Example 1: This example illustrates the simple form validation using jQuery.

HTML

<!DOCTYPE html>
<html>

<head>
    <!-- Latest compiled and minified CSS -->
    <link rel="stylesheet" href=
"https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
    <!-- jQuery library -->
    <script src=
"https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js">
    </script>
    <!-- Popper JS -->
    <script src=
"https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js">
    </script>
    <!-- Latest compiled JavaScript -->
    <script src=
"https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js">
    </script>
</head>

<body>
    <h1 class="text-center text-success">
        Welcome to GeeksforGeeks
    </h1>
    <p class="text-center">
        FORM VALIDATION USING JQUERY
    </p>

    <div class="container">
        <div class="col-lg-8
                    m-auto d-block">
            <form>
                <div class="form-group">
                    <label for="user">
                        Username:
                    </label>
                    <input type="text" 
                           name="username" 
                           id="usernames" 
                           class="form-control">
                    <h5 id="usercheck" 
                        style="color: red;">
                        **Username is missing
                    </h5>
                </div>

                <div class="form-group">
                    <label for="user">
                        Email:
                    </label>
                    <input type="email" 
                           name="email" 
                           id="email" required 
                           class="form-control">
                    <small id="emailvalid" 
                           class="form-text text-muted invalid-feedback">
                        Your email must be a valid email
                    </small>
                </div>

                <div class="form-group">
                    <label for="password">
                        Password:
                    </label>
                    <input type="password" 
                           name="pass" 
                           id="password" 
                           class="form-control">
                    <h5 id="passcheck" 
                        style="color: red;">
                        **Please Fill the password
                    </h5>
                </div>

                <div class="form-group">
                    <label for="conpassword">
                        Confirm Password:
                    </label>
                    <input type="password"
                           name="username" 
                           id="conpassword"
                           class="form-control">
                    <h5 id="conpasscheck" 
                        style="color: red;">
                        **Password didn't match
                    </h5>
                </div>

                <input type="submit"
                       id="submitbtn"
                       value="Submit"
                       class="btn btn-primary">
            </form>
        </div>
    </div>

    <!-- Including app.js jQuery Script -->
    <script src="app.js"></script>
</body>

</html>

JavaScript

$(document).ready(function () {

    // Validate Username
    $("#usercheck").hide();
    let usernameError = true;
    $("#usernames").keyup(function () {
        validateUsername();
    });

    function validateUsername() {
        let usernameValue = $("#usernames").val();
        if (usernameValue.length === "") {
            $("#usercheck").show();
            usernameError = false;
            return false;
        } else if (usernameValue.length < 3 || usernameValue.length > 10) {
            $("#usercheck").show();
            $("#usercheck").html("**length of username must be between 3 and 10");
            usernameError = false;
            return false;
        } else {
            $("#usercheck").hide();
            usernameError = true;
        }
    }

    // Validate Email
    const email = document.getElementById("email");
    let emailError = true;
    email.addEventListener("blur", () => {
        let regex = 
        /^([_\-\.0-9a-zA-Z]+)@([_\-\.0-9a-zA-Z]+)\.([a-zA-Z]){2,7}$/;
        let s = email.value;
        if (regex.test(s)) {
            email.classList.remove("is-invalid");
            emailError = true;
        } else {
            email.classList.add("is-invalid");
            emailError = false;
        }
    });

    // Validate Password
    $("#passcheck").hide();
    let passwordError = true;
    $("#password").keyup(function () {
        validatePassword();
    });
    function validatePassword() {
        let passwordValue = $("#password").val();
        if (passwordValue.length === "") {
            $("#passcheck").show();
            passwordError = false;
            return false;
        }
        if (passwordValue.length < 3 || passwordValue.length > 10) {
            $("#passcheck").show();
            $("#passcheck").html(
                "**length of your password must be between 3 and 10"
            );
            $("#passcheck").css("color", "red");
            passwordError = false;
            return false;
        } else {
            $("#passcheck").hide();
            passwordError = true;
        }
    }

    // Validate Confirm Password
    $("#conpasscheck").hide();
    let confirmPasswordError = true;
    $("#conpassword").keyup(function () {
        validateConfirmPassword();
    });
    function validateConfirmPassword() {
        let confirmPasswordValue = $("#conpassword").val();
        let passwordValue = $("#password").val();
        if (passwordValue !== confirmPasswordValue) {
            $("#conpasscheck").show();
            $("#conpasscheck").html("**Password didn't Match");
            $("#conpasscheck").css("color", "red");
            confirmPasswordError = false;
            return false;
        } else {
            $("#conpasscheck").hide();
            confirmPasswordError = true;
        }
    }

    // Submit button
    $("#submitbtn").click(function () {
        validateUsername();
        validatePassword();
        validateConfirmPassword();
        email.dispatchEvent(new Event('blur')); 
        
        if (
            usernameError &&
            passwordError &&
            confirmPasswordError &&
            emailError
        ) {
            return true;
        } else {
            return false;
        }
    });
});

Output:

Validation using an inbuilt jQuery validation plugin

In this part, you get to know about the inbuilt validation method of jQuery. Create an index.html file and copy the following code.

Example : This example describes the form validation with the help of a built-in jQuery validation plugin.

HTML

<!doctype html>
<html>

<head>
    <meta charset="utf-8">
    
    <!-- below we are including the 
         jQuery and jQuery plugin .js files -->
    <script src=
"https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js">
      </script>
    <script src=
"https://cdn.jsdelivr.net/jquery.validation/1.16.0/jquery.validate.min.js">
      </script>
    <script src=
"https://cdn.jsdelivr.net/jquery.validation/1.16.0/additional-methods.min.js">
      </script>
    
</head>

<body>
    <form class="cmxform" 
          id="commonForm" 
          method="get" 
          action="form-handler.html"
          autocomplete="off">
        <fieldset>
            <legend>GFG Form</legend>

            <p>
                <label for="cname">
                      Name <span>(required at least 2 character)</span>
                  </label>
              
                <!--User have to set the constraints
                    in attribute form-->
                <input id="cname" 
                       name="name" 
                       minlength="2" 
                       type="text" required>
            </p>
            <p>
                <label for="cemail">
                      Email <span>(required, won't be published)</span>
                  </label>
                <input id="cemail" 
                       type="email" 
                       name="email" required>
            </p>
            <p>
                <label for="curl">
                      URL <span>(Optional)</span>
                  </label>
                <input id="curl" type="url" name="url">
            </p>
            <p>
                <label for="ccomment">
                      Your comment<span>(required)</span>
                  </label>
                <textarea id="ccomment" 
                          name="comment" required>
                  </textarea>
            </p>
            <p>
                <input class="submit" 
                       type="submit" 
                       value="submit">
            </p>
        </fieldset>
    </form>
</body>

</html>

JavaScript

// User have to use id for 
// form and call validate method
$("#commonForm").validate();

Output:

jQuery is an open-source JavaScript library that simplifies the interactions between an HTML/CSS document, It is widely famous for its philosophy of “Write less, do more".

You can learn jQuery from the ground up by following this jQuery Tutorial and jQuery Examples.

How to submit a form using ajax in jQuery ?

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Article Tags :

Form Validation using jQuery

Using plain jQuery

Validation using an inbuilt jQuery validation plugin

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