Tryit Editor v2.7

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<style>
[class|=top] {
    background: yellow;
}
</style>

<script>
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "//hm.baidu.com/hm.js?73c27e26f610eb3c9f3feb0c75b03925";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
</script>
</head>
<body>

<h1 class="top-header">Welcome</h1>
<p class="top-text">Hello world!</p>
<p class="content">Are you learning CSS?</p>

<p><b>Note:</b> For [<i>attribute</i>|=<i>value</i>] to work in IE8 and earlier, a DOCTYPE must be declared.</p>

</body>
</html>