获取按键的keyCode

<SCRIPT>
function fnTrapKD(){
   if(oTrap.checked){
      oOutput.innerText+="[trap = " + event.keyCode + "]";
      event.returnValue=false;
   }
   else{
      oOutput.innerText+=String.fromCharCode(event.keyCode);
   }
}
</SCRIPT>
<INPUT TYPE="checkbox" ID="oTrap" checked>显示按键的keyCode<br />
在该输入框按键：<INPUT ID="oExample" TYPE="text" onkeydown="fnTrapKD()"><br />
<TEXTAREA ID="oOutput" ROWS="10" COLS="50">
</TEXTAREA>

--------取得按键的ASCII吗的值

<body onKeyDown="alert(event.keyCode)">按键盘看看,

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