Edit in JSFiddle

<form class="well">
    <div class="control-group">
        <input type="text" placeholder="placeholder text" />
    </div>
    <div class="control-group">
        <textarea placeholder="placeholder text (will disappear after typing)" cols="30" rows="5"></textarea>
    </div>
</form>

input::-webkit-input-placeholder, textarea::-webkit-input-placeholder {
    color: #555;
}
input:focus::-webkit-input-placeholder, textarea:focus::-webkit-input-placeholder {
    color: #777;
}
input:-moz-placeholder, textarea:-moz-placeholder {  
    color: #555;  
}