JavaScript 获取图片 alt 属性值的方法

<!DOCTYPE html>
<html>
<body>
<img id="compman" src="compman.gif" alt="Crazy computerman" 
width="107" height="98">
<p>The value of the alt atrribute is:
<script>
document.write(document.getElementById("compman").alt);
</script>
</p>
</body>
</html>