New year card coding!

yky_code.js

var str = ["HOGE", "SOME", "TEXT", "IN", "HERE", "PIYO"];
for(var t in str) {
    var c = t + 2;
    t = parseInt(t);
    console.log(t+1);
    for(var i in str[t]) {
        var right = str[t].charCodeAt(i) + (t+1);
        var left = str[t].charCodeAt(i) - (t+1);
        if(right > 90) right -= 26;
        if(left < 65) left += 26;
        if(c <= (t+1)) console.log(String.fromCharCode(right + 32));
        else {
            console.log(String.fromCharCode(left));
            c = 0;
        }
        c++;
    }
    console.log("------------------------");
}