let key = ‘‘; if (e.key) { // onKeyDown，对应的e.key ＝ ‘ArrowDown ArrowUp Enter’等 key = e.key; } else { let code = e.which || e.keyCode; key = String.fromCharCode(code); }
e.key && e.which && e.keyCode
原文：http://www.cnblogs.com/Candybunny/p/7086728.html
