input:focus::-webkit-input-placeholder,
textarea:focus::-webkit-input-placeholder { /* WebKit browsers */
  color:transparent;
}

input:focus:-moz-placeholder,
textarea:focus:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
  color:transparent;
}

input:focus::-moz-placeholder,
textarea:focus::-moz-placeholder { /* Mozilla Firefox 19+ */
  color:transparent;
}

input:focus:-ms-input-placeholder,
textarea:focus:-ms-input-placeholder { /* Internet Explorer 10+ */
  color:transparent;
}