Bootstrap 4 input error

<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.6/css/bootstrap.min.css" integrity="sha384-rwoIResjU2yc3z8GV/NPeZWAv56rSmLldC3R/AZzGRnGxQQKnKkoFVhFQhNUwEyJ" crossorigin="anonymous">

<!--
  Title: bootstrap 4 input error
-->
<!--Go to https://www.w3schools.com/bootstrap4/bootstrap_forms.asp for more info-->
<form action="/action_page.php" class="was-validated">
  <div class="form-group">
    <label for="uname">Username:</label>
    <input type="text" class="form-control" id="uname" placeholder="Enter username" name="uname" required>
    <div class="valid-feedback">Valid.</div>
    <div class="invalid-feedback">Please fill out this field.</div>
  </div>
  <div class="form-group">
    <label for="pwd">Password:</label>
    <input type="password" class="form-control" id="pwd" placeholder="Enter password" name="pswd" required>
    <div class="valid-feedback">Valid.</div>
    <div class="invalid-feedback">Please fill out this field.</div>
  </div>
  <div class="form-group form-check">
    <label class="form-check-label">
      <input class="form-check-input" type="checkbox" name="remember" required> I agree on blabla.
      <div class="valid-feedback">Valid.</div>
      <div class="invalid-feedback">Check this checkbox to continue.</div>
    </label>
  </div>
  <button type="submit" class="btn btn-primary">Submit</button>
</form>

Source: stackoverflow.com

Similar codes

0 vote328 views1 answer
Css inherit class
CSS
0 vote265 views1 answer
Target button of fileinput css
CSS
0 vote296 views1 answer
Css good black color
CSS
0 vote266 views1 answer
Parcel-bundler bulma css
CSS
0 vote269 views1 answer
Ion-img border radius
CSS
1 vote274 views1 answer
Ul remove dots
CSS
0 vote268 views1 answer
Resize logo html css
CSS
0 vote314 views1 answer
Global css cannot be imported from files other than your
CSS
1 vote259 views1 answer
Animated website using html and css
CSS
22 votes295 views6 answers
Box shadow css
CSS