【get】
<!DOCTYPE html>
<html>
<body>
<div class="des">
<h1>Test</h1>
<div class="desleft">
<p>Lorem Ipsum.</p>
</div>
<div class="Right">
<button>Test</button>
</div>
</div>
<script type='text/javascript'>
console.log(document.getElementsByClassName("desleft")[0].previousSibling.previousSibling.tagName)
</script>
</body>
</html>
