input::-webkit-input-placeholder{
color:#4e4e4e;
}
input::-moz-placeholder{
color:#4e4e4e;
}
input:-moz-placeholder{
color:#4e4e4e;
}
input:-ms-input-placeholder{
color:#4e4e4e;
}
原文：https://www.cnblogs.com/ly-qingqiu/p/11097473.html