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<html><head><style>.democlass { color: red;}</style></head><body><h1 class="democlass">Hello World</h1><p id="demo">Click the button to remove the class attribute from the h1 element.</p><button onclick="myFunction()">Try it</button><script>function myFunction() { document.getElementsByTagName("H1")[0].removeAttribute("class"); }</script></body></html>