<link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <link href="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css"> <script src="//maxcdn.bootstrapcdn.com/bootstrap/4.1.1/js/bootstrap.min.js"></script> <script src="//cdnjs.cloudflare.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script> <!------ Include the above in your HEAD tag ----------> <!-- Button trigger modal --> <button class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">Launch demo modal</button> <!-- Modal --> <div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true"> <div class="modal-center"> <div class="modal-dialog .modal-align-center"> <div class="modal-content"> <div class="modal-header"> <h4 class="modal-title" id="myModalLabel">Modal title</h4> <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">×</span><span class="sr-only">Close</span> </button> </div> <div class="modal-body"> <form class="form-horizontal" method="#" id="form_sign"> <div class="row"> <div class="col-md-12"> <div class="form-group"> <div class="col-md-12"> <label for="pwd">Usuario :</label> <input required="" class="form-control input" type="text" id="email" onkeypress="saltar(event,'password')" required="required" onkeyup="validatePassword(this.value);" autocomplete="off" value="" autofocus="true" > </div> </div> </div> <div class="col-md-12"> <!-- <div class="form-group"> <div class="col-md-12"> <label for="pwd">Contraseña :</label> <input required="" class="form-control input" type="password" id="password" autocomplete="off" value="" autofocus="true" > <div class="input-group-append"> <button id="show_password" class="btn btn-primary" type="button" onclick="mostrarPassword()"> <span class="fa fa-eye-slash icon"></span> </button> </div> </div> </div>--> <label for="pwd">Contraseña :</label> <div class="input-group"> <input required="" class="form-control input" type="password" id="password" autocomplete="off" value="" autofocus="true"> <span class="input-group-addon"><span onclick="mostrarPassword()" class="fa fa-eye-slash icon"></span></span> </div> </div> </div> <div class="control-group"> <label class="control-label" for="signin"></label> <div class="controls"> <button id="signin_button" name="signin" class="btn btn-primary btn-block">Login</button> <input type="button" id="cancelar" name="cancelar" class="btn btn-default btn-block" onclick="cloceModalLogin();" value="Cancelar"> </div> </div> </form> </div> <div class="modal-footer"> <button type="button" class="btn btn-default" data-dismiss="modal">Close</button> <button type="button" class="btn btn-primary">Save changes</button> </div> </div> </div> </div> </div>

.modal-center { display:table; height: 100%; width: 100%; } .modal-align-center {: table-cell;vertical-align: middle;} .modal-content {height:inherit;margin: 0 auto;}