Question

I need help with a regex and I don’t know how to go about this.

How can I prevent the user from submitting until they enter a proper email?

The email format must be like this [e-mail]

the email address that should be accepted can only have the domain @bri.golia.com, anything else should not let the user submit the form, how can I go about this?

            <form method="post" action="site.com/mail.php" name="SampleForm" enctype="multipart/form-data">


                        <div class="info">
                            <h2 class="forms_heading" name="Contact">Contact Information</h2>
                                <br />
                                <div class="required">
                                    <label for="name">Name:</label>
                                    <input type="text" for="name" id="name" name="RequesterName" required="required"  />

                                </div>
                                <div class="required">
                                    <label for="email">E-mail:</label>
                                    <input type="text" for="email" id="email" name="RequesterEmail" required="required"   />
                                </div>

                                <div class="required">
                                    <label for="phone">Phone:</label>
                                    <input type="text" for="phone" id="phone" name="RequesterPhone" required="required"   />
                                </div>

                                <br />
                                <br />
                        </div><!-- end info -->





                            <br />
                            <input type="submit" value="Submit" class="submit_button"  />

Answer 1

Add the pattern attribute with the regex:

<input type="text" for="email" id="email" name="RequesterEmail" required="required" pattern="\b[A-Za-z0-9._%+-]+@bri\.golia\.com\b"  />

Also see my jsfiddle.

=== UPDATE ===

To change the error text overwrite the invalid method:

document.getElementById('email').oninvalid = function(e) {
    e.target.setCustomValidity('');
    if (!e.target.validity.valid) {
        e.target.setCustomValidity("My custom text.");
    }
};

Also see my updated jsfiddle.