W3School TIY Editor
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<!DOCTYPE html> <html> <body> <p>输入您的年龄然后点击这个按钮：</p> <input id="age" value="18" /> <button onclick="myFunction()">试一试</button> <p id="demo"></p> <script> function myFunction() { var age, voteable; age = document.getElementById("age").value; voteable = (age < 18) ? "好年轻":"够成熟"; document.getElementById("demo").innerHTML = voteable; } </script> </body> </html>