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<!DOCTYPE html> <html> <body> <select id="mySelect"> <option>Apple</option> <option>Orange</option> <option>Pineapple</option> <option>Banana</option> </select> <p>Click the button to deselect options.</p> <button onclick="myFunction()">Try it</button> <script> function myFunction() { document.getElementById("mySelect").selectedIndex = "-1"; } </script> </body> </html>