点击运行
<!DOCTYPE html> <html> <body> <h1>JavaScript 字符串方法</h1> <p>把字符串转换为大写：</p> <button onclick="myFunction()">试一试</button> <p id="demo">Hello World!</p> <script> function myFunction() { var text = document.getElementById("demo").innerHTML; document.getElementById("demo").innerHTML = text.toUpperCase(); } </script> </body> </html>
运行结果
