place-holder样式

input::-webkit-input-placeholder, textarea::-webkit-input-placeholder { color: #777; }
input:-moz-placeholder, textarea:-moz-placeholder { color: #777; }
input::-moz-placeholder, textarea::-moz-placeholder { color: #777; }
input:-ms-input-placeholder, textarea:-ms-input-placeholder { color: #777; }
/*focus*/
input:focus::-webkit-input-placeholder, textarea:focus::-webkit-input-placeholder { color: #fff; }
input:focus:-moz-placeholder, textarea:focus:-moz-placeholder { color: #fff; }
input:focus::-moz-placeholder, textarea:focus::-moz-placeholder { color: #fff; }
input:focus:-ms-input-placeholder, textarea:focus:-ms-input-placeholder { color: #fff; }