51help TIY
码：
<!DOCTYPE html> <html> <head> <script> function myFunction() { var x=document.getElementById("fname"); x.value=x.value.toUpperCase(); } </script> </head> <body> 字符：<input type="text" id="fname" onchange="myFunction()"> <p>数。</p> </body> </html>
查看结果: