javascript - alert letters by name on pressing keyboard buttons without using a switch statement -

here have simple piece of code.i want alert letters [a-z] on pressing buttons on keyboard representing letters.till alerting keycodes.i know can whit switch statement.but large piece of switch statement. questions are:

1.is there way can alert every letters name on keypress without switch statement?

2.left,right,up,down arrow keys not alerting keycode numbers.why so??how can overcome problem??

(function(){     document.body.addeventlistener('keypress',function(e){             alert(e.keycode);     }); })(); 

to show letters keycode:

alert (string.fromcharcode(e.keycode)); 

to address problems arrow-keys not showing keycodes (37 - 40):

(function(){      document.body.addeventlistener('keyup',function(e){        // keycodes of arrow keys, matched appropriate        // unicode arrow symbol:        var directionals = {          '38' : 8593, // string.fromcharcode(38) => &          '39' : 8594, // string.fromcharcode(39) => '          '40' : 8595, // string.fromcharcode(40) => (          '37' : 8592 // string.fromcharcode(37) => %        },            // if there falsey value directionals object,            // use e.keycode unchanged; otherwise substitute            // e.keycode above-supplied arrow-character:            keycodetouse = !directionals[e.keycode] ? e.keycode : directionals[e.keycode];        // don't alerts; access console (in browsers) press 'f12':        console.log(string.fromcharcode(keycodetouse));      });  })();

html, body {    background-color: rgba(255,255,180, 0.5);    height: 100%;  }

the problem (for whatever reason) arrow keys return keycodes on keyup , keydown, not on keypress. further, string.fromcharcode() using key codes (as shown in javascript, above) return characters not, in fact, arrows. so, have use alternate unicode references (supplied above, in javascript).

references:

• string.fromcharcode().