get bootstrap 4 form-control element only code example

Example 1: class required bootstrap 3

<form class="needs-validation" novalidate>
  <div class="form-row">
    <div class="col-md-4 mb-3">
      <label for="validationCustom01">First name</label>
      <input type="text" class="form-control" id="validationCustom01" placeholder="First name" value="Mark" required>
      <div class="valid-feedback">
        Looks good!
      </div>
    </div>
    <div class="col-md-4 mb-3">
      <label for="validationCustom02">Last name</label>
      <input type="text" class="form-control" id="validationCustom02" placeholder="Last name" value="Otto" required>
      <div class="valid-feedback">
        Looks good!
      </div>
    </div>
    <div class="col-md-4 mb-3">
      <label for="validationCustomUsername">Username</label>
      <div class="input-group">
        <div class="input-group-prepend">
          <span class="input-group-text" id="inputGroupPrepend">@</span>
        </div>
        <input type="text" class="form-control" id="validationCustomUsername" placeholder="Username" aria-describedby="inputGroupPrepend" required>
        <div class="invalid-feedback">
          Please choose a username.
        </div>
      </div>
    </div>
  </div>
  <div class="form-row">
    <div class="col-md-6 mb-3">
      <label for="validationCustom03">City</label>
      <input type="text" class="form-control" id="validationCustom03" placeholder="City" required>
      <div class="invalid-feedback">
        Please provide a valid city.
      </div>
    </div>
    <div class="col-md-3 mb-3">
      <label for="validationCustom04">State</label>
      <input type="text" class="form-control" id="validationCustom04" placeholder="State" required>
      <div class="invalid-feedback">
        Please provide a valid state.
      </div>
    </div>
    <div class="col-md-3 mb-3">
      <label for="validationCustom05">Zip</label>
      <input type="text" class="form-control" id="validationCustom05" placeholder="Zip" required>
      <div class="invalid-feedback">
        Please provide a valid zip.
      </div>
    </div>
  </div>
  <div class="form-group">
    <div class="form-check">
      <input class="form-check-input" type="checkbox" value="" id="invalidCheck" required>
      <label class="form-check-label" for="invalidCheck">
        Agree to terms and conditions
      </label>
      <div class="invalid-feedback">
        You must agree before submitting.
      </div>
    </div>
  </div>
  <button class="btn btn-primary" type="submit">Submit form</button>
</form>

<script>
// Example starter JavaScript for disabling form submissions if there are invalid fields
(function() {
  'use strict';
  window.addEventListener('load', function() {
    // Fetch all the forms we want to apply custom Bootstrap validation styles to
    var forms = document.getElementsByClassName('needs-validation');
    // Loop over them and prevent submission
    var validation = Array.prototype.filter.call(forms, function(form) {
      form.addEventListener('submit', function(event) {
        if (form.checkValidity() === false) {
          event.preventDefault();
          event.stopPropagation();
        }
        form.classList.add('was-validated');
      }, false);
    });
  }, false);
})();
</script>

Example 2: bootstrap forms examples

<!-- Default form login -->
<form class="text-center border border-light p-5" action="#!">

    <p class="h4 mb-4">Sign in</p>

    <!-- Email -->
    <input type="email" id="defaultLoginFormEmail" class="form-control mb-4" placeholder="E-mail">

    <!-- Password -->
    <input type="password" id="defaultLoginFormPassword" class="form-control mb-4" placeholder="Password">

    <div class="d-flex justify-content-around">
        <div>
            <!-- Remember me -->
            <div class="custom-control custom-checkbox">
                <input type="checkbox" class="custom-control-input" id="defaultLoginFormRemember">
                <label class="custom-control-label" for="defaultLoginFormRemember">Remember me</label>
            </div>
        </div>
        <div>
            <!-- Forgot password -->
            <a href="">Forgot password?</a>
        </div>
    </div>

    <!-- Sign in button -->
    <button class="btn btn-info btn-block my-4" type="submit">Sign in</button>

    <!-- Register -->
    <p>Not a member?
        <a href="">Register</a>
    </p>

    <!-- Social login -->
    <p>or sign in with:</p>

    <a href="#" class="mx-2" role="button"><i class="fab fa-facebook-f light-blue-text"></i></a>
    <a href="#" class="mx-2" role="button"><i class="fab fa-twitter light-blue-text"></i></a>
    <a href="#" class="mx-2" role="button"><i class="fab fa-linkedin-in light-blue-text"></i></a>
    <a href="#" class="mx-2" role="button"><i class="fab fa-github light-blue-text"></i></a>

</form>
<!-- Default form login -->