js中，实现对键盘按键的监听：

    <script>
       function keyUp(e) {
              var currKey=0,e=e||event;
              currKey=e.keyCode||e.which||e.charCode;
              var keyName = String.fromCharCode(currKey);
              alert("按键码: " + currKey + " 字符: " + keyName);
          }
       document.onkeyup = keyUp;
    </script>