<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
:-moz-placeholder { /* Mozilla Firefox 4 to 18 */
color: #f00;
}
::-moz-placeholder { /* Mozilla Firefox 19+ */
color: #f00;
}
input:-ms-input-placeholder,
textarea:-ms-input-placeholder {
color: #f00;
}
input::-webkit-input-placeholder,
textarea::-webkit-input-placeholder {
color: #f00;
}
</style>
</head>
<body>
<input type="text" name="" id="" value="" placeholder="请输入您要搜素的内容"/>
</body>
</html>
原文：http://my.oschina.net/CodingPeasant/blog/514105