Html部分
<input type="search" name="user_search" placeholder="Search W3School" />
CSS部分
::-webkit-input-placeholder {
color: red;
}
:-moz-placeholder {/* Firefox 18- */
color: red;
}
::-moz-placeholder{/* Firefox 19+ */
color: red;
}
:-ms-input-placeholder {
color: red;
}
