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<html><title>W3.JS</title><script src="https://www.w3schools.com/lib/w3.js"></script><body><p>Click the button to hide all elements in this document.</p><button onclick="w3.hide('*')">Hide</button><h2>This is a heading</h2><p>This is a paragraph.</p><p>This is another paragraph.</p></body></html>