works only in bootstrap <div class="button-group"> <button type="button" class="btn btn-default btn-sm dropdown-toggle form-control" data-toggle="dropdown"> Select Country <span class="caret"></span> </button> <ul class="dropdown-menu form-control" style="height:160px; overflow-x: hidden;"> <? $sql="SELECT * from country"; $result=mysqli_query($con,$sql); if(mysqli_num_rows($result)>0) { while($row=mysqli_fetch_assoc($result)) { ?> <li class="form-control"> <input type="checkbox" value="<? echo $row['country_name'];?>" name ="chk[]"/> <? echo $row['country_name'];?></li> ...