caesar cipher javascript
function rot13(str) {
var charcode = [];
var words = [];
for(let i = 0; i < str.length; i++){
  
  var asc = str.charCodeAt(i)
  
  charcode.push(asc)
}
var converted = charcode.map(function(a){
  return a-13
})
console.log(converted)
converted.forEach((letter)=>{
 if(letter >= 65){
  var final =String.fromCharCode(letter)
  words.push(final)
 }
 else if(letter>=52){
   final = String.fromCharCode(letter+26)
   words.push(final)
 }
 else {
   final = String.fromCharCode(letter+13)
   words.push(final)
 }
 
})
return words.join("")
}
console.log(rot13("SERR YBIR?"));