<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>

// 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);})();

<form class="needs-validation" novalidate>  <div class="form-row">    <div class="col-md-4 mb-3">      <label for="validationTooltip01">First name</label>      <input type="text" class="form-control" id="validationTooltip01" placeholder="First name" value="Mark" required>      <div class="valid-tooltip">        Looks good!      </div>    </div>    <div class="col-md-4 mb-3">      <label for="validationTooltip02">Last name</label>      <input type="text" class="form-control" id="validationTooltip02" placeholder="Last name" value="Otto" required>      <div class="valid-tooltip">        Looks good!      </div>    </div>    <div class="col-md-4 mb-3">      <label for="validationTooltipUsername">Username</label>      <div class="input-group">        <div class="input-group-prepend">          <span class="input-group-text" id="validationTooltipUsernamePrepend">@</span>        </div>        <input type="text" class="form-control" id="validationTooltipUsername" placeholder="Username" aria-describedby="validationTooltipUsernamePrepend" required>        <div class="invalid-tooltip">          Please choose a unique and valid username.        </div>      </div>    </div>  </div>  <div class="form-row">    <div class="col-md-6 mb-3">      <label for="validationTooltip03">City</label>      <input type="text" class="form-control" id="validationTooltip03" placeholder="City" required>      <div class="invalid-tooltip">        Please provide a valid city.      </div>    </div>    <div class="col-md-3 mb-3">      <label for="validationTooltip04">State</label>      <input type="text" class="form-control" id="validationTooltip04" placeholder="State" required>      <div class="invalid-tooltip">        Please provide a valid state.      </div>    </div>    <div class="col-md-3 mb-3">      <label for="validationTooltip05">Zip</label>      <input type="text" class="form-control" id="validationTooltip05" placeholder="Zip" required>      <div class="invalid-tooltip">        Please provide a valid zip.      </div>    </div>  </div>  <button class="btn btn-primary" type="submit">Submit form</button></form>