Ejemplo
Vista Previa
<!doctype html> <html> <head> <title>Prueba de Bootstrap 4</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous"> </head> <body> <div class="container"> <form> <div class="form-group"> <label for="control1">Seleccione un elemento</label> <select class="form-control" id="control1" name="control1"> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> </div> <div class="form-group"> <label for="control2">Seleccione varios elementos</label> <select multiple class="form-control" id="control2" name="control2"> <option>1</option> <option>2</option> <option>3</option> <option>4</option> <option>5</option> </select> </div> <button type="submit" class="btn btn-default">Enviar</button> </form> </div> </body> </html>
No tiene disponible el navegador la capacidad de iframe