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<!DOCTYPE html> <html> <body> <h1>JavaScript Prompt</h1> <button onclick="myFunction()">试一试</button> <p id="demo"></p> <script> function myFunction() { var txt; var person = prompt("请输入您的名字：", "哈利波特"); if (person == null || person == "") { txt = "用户取消输入"; } else { txt = "你好，" + person + "！今天过得好吗？"; } document.getElementById("demo").innerHTML = txt; } </script> </body> </html>