源代码
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>享学课堂</title> </head> <body> <p>输入你的年龄并点击按钮:</p> <input id="age" value="18" /> <button onclick="myFunction()">试试</button> <p id="demo"></p> <script> function myFunction() { var age, voteable; age = document.getElementById("age").value; voteable = (age < 18) ? "Too young":"Old enough"; document.getElementById("demo").innerHTML = voteable + " to vote."; } </script> </body> </html>
运行结果