#myBtnTop {
  display: none;
  position: fixed;
  top: 70px;
  right: 10px;
  z-index: 199;
  font-size: 14px;
  border: none;
  outline: none;
  background-color: blue;
  color: white;
  cursor: pointer;
  padding: 5px;
  border-radius: 4px;
}

#myBtnTopLeft {
  display: none;
  position: fixed;
  top: 70px;
  left: 10px;
  z-index: 199;
  font-size: 14px;
  border: none;
  outline: none;
  background-color: blue;
  color: white;
  cursor: pointer;
  padding: 5px;
  border-radius: 4px;
}

#myBtnBottom {
  display: none;
  position: fixed;
  bottom: 20px;
  right: 10px;
  z-index: 199;
  font-size: 14px;
  border: none;
  outline: none;
  background-color: green;
  color: white;
  cursor: pointer;
  padding: 5px;
  border-radius: 4px;
}

#myBtnBottomLeft {
  display: none;
  position: fixed;
  bottom: 20px;
  left: 10px;
  z-index: 199;
  font-size: 14px;
  border: none;
  outline: none;
  background-color: green;
  color: white;
  cursor: pointer;
  padding: 5px;
  border-radius: 4px;
}

#myBtnTop:hover {
  background-color: #555;
}

#myBtnTopLeft:hover {
  background-color: #555;
}

#myBtnBottom:hover {
  background-color: #555;
}

#myBtnBottomLeft:hover {
  background-color: #555;
}