​x
 
<!DOCTYPE html>
<html>
<body>
​
<h3>如何访问 HEADER 元素的演示</h3>
​
<article>
  <header id="myHeader">
  <h3>Internet Explorer 9</h3>
  </header>
  <p>Windows Internet Explorer 9 (abbreviated as IE9) was released to
  the public on March 14, 2011 at 21:00 PDT.....</p>
</article>
​
<p>单击按钮将标题元素的颜色设置为红色。</p>
​
<button onclick="myFunction()">试一试</button>
​
<script>
function myFunction() {
  var x = document.getElementById("myHeader");
  x.style.color = "red";
}
</script>
​
</body>
</html>
​
​