数字、大小写字母的字符编码

<script>
    var html=""
    for(var i=48;i<58;i++){
        html+=i+":"+String.fromCharCode(i)+"\n"
    }
    for(var i=65;i<91;i++){
        html+=i+":"+String.fromCharCode(i)+"\n"
    }
    for(var i=97;i<123;i++){
        html+=i+":"+String.fromCharCode(i)+"\n"
    }
    document.write(html)
</script>

　　48:0 49:1 50:2 51:3 52:4 53:5 54:6 55:7 56:8 57:9 65:A 66:B 67:C 68:D 69:E 70:F 71:G 72:H 73:I 74:J 75:K 76:L 77:M 78:N 79:O 80:P 81:Q 82:R 83:S 84:T 85:U 86:V 87:W 88:X 89:Y 90:Z 97:a 98:b 99:c 100:d 101:e 102:f 103:g 104:h 105:i 106:j 107:k 108:l 109:m 110:n 111:o 112:p 113:q 114:r 115:s 116:t 117:u 118:v 119:w 120:x 121:y 122:z