<input placeholder="我是红色的！">

input::placeholder {
  color: red;
  font-size: 1.2em;
  font-style: italic;
}

input::-webkit-input-placeholder {
    color: #999;
}
/* IE10+ */
input:-ms-input-placeholder {
    color: #999;
}
/* Firefox4-18 */
input:-moz-placeholder {
    color: #999;
}
/* Firefox19+ */
input::-moz-placeholder {
    color: #999;
}
input::placeholder {
  color: #999;
}

textarea::-webkit-input-placeholder {
    color: #999;
}
/* IE10+ */
textarea:-ms-input-placeholder {
    color: #999;
}
/* Firefox4-18 */
textarea:-moz-placeholder {
    color: #999;
}
/* Firefox19+ */
textarea::-moz-placeholder {
    color: #999;
}
textarea::placeholder {
  color: #999;
}