For modern browsers, use just the ::placeholder pseudo element:
textarea::placeholder {
color: #0bf;
}
Legacy and modern browsers:
textarea:-moz-placeholder, /* Firefox 18- */
textarea::-moz-placeholder, /* Firefox 19+ */
textarea:-ms-input-placeholder, /* IE 10+ */
textarea::-webkit-input-placeholder, /* Webkit based */
textarea::placeholder { /* Modern browsers */
color: #0bf;
}<textarea placeholder="test"></textarea>And related to your code, wrap in quotes:
onchange="{(e) => this.props.handleUpdateQuestion(e, firstQuestion.Id)}"