event.which === 27 code example

Example 1: jquery event keycode

$('#someTextBox').keypress(function(event){
    var keycode = (event.keyCode ? event.keyCode : event.which);
    if(keycode == '13'){
        alert('You pressed a "enter" key in textbox');  
    }
});

Example 2: keycode letters

0	48
1	49
2	50
3	51
4	52
5	53
6	54
7	55
8	56
9	57
a	65
b	66
c	67
d	68	
e	69
f	70
g	71
h	72
i	73
j	74
k	75
l	76
m	77
n	78
o	79
p	80
q	81
r	82
s	83
t	84
u	85
v	86
w	87
x	88
y	89
z	90