Smooth removal of placeholder text on focus

gistfile1.txt

input {
  border: solid 1px #bbb;
  padding: 5px;
}

input:focus::-webkit-input-placeholder {
  color: transparent;
  -webkit-transition: color 0.5s 0.5s ease;
  transition: color 0.5s 0.5s ease;
}

input:focus:-moz-placeholder {
  color: transparent;
  -moz-transition: color 0.5s 0.5s ease;
  transition: color 0.5s 0.5s ease;
}

input:focus::-moz-placeholder {
  color: transparent;
}

input:focus:ms-input-placeholder {
  color: transparent;
  -ms-transition: color 0.5s 0.5s ease;
  transition: color 0.5s 0.5s ease;
}