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<html><style>.democlass { color: red;}</style><body><h1>The Element Object</h1><h2>The setAttributeNode() Method</h2><p>Click "Change" to set the class attribute node of the first header.</p><button onclick="myFunction()">Change</button><script>function myFunction() { const attr = document.createAttribute("class"); attr.value = "democlass"; const element = document.getElementsByTagName("H1")[0]; element.setAttributeNode(attr); }</script></body></html>