51help TIY
码：
<html> <head> <script type="text/javascript"> function writeMessage() { document.forms[0].mySecondInput.value=document.forms[0].myInput.value } </script> </head> <body> <p>发生 onkeyup 事件。</p> <form> 消息：<br /> <input type="text" name="myInput" onkeyup="writeMessage()" size="20"> <input type="text" name="mySecondInput" size="20"> </form> </body> </html>
查看结果: