js中对按键的监听详解编程语言

js中，实现对键盘按键的监听：

function keyUp> 这里输入引用文本p(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;

alert信息例如：”按键码: 81 字符: Q”