ตรวจสอบ CSS ตามมาตรฐาน XHTML

<p>
    <a href="http://jigsaw.w3.org/css-validator/">
        <img style="border:0;width:88px;height:31px"
            src="http://jigsaw.w3.org/css-validator/images/vcss"
            alt="Valid CSS!" />
    </a>
</p>

<p>
<a href="http://jigsaw.w3.org/css-validator/">
    <img style="border:0;width:88px;height:31px"
        src="http://jigsaw.w3.org/css-validator/images/vcss-blue"
        alt="Valid CSS!" />
</a>
</p>