function r(a){
var rotated = 97+((a.charCodeAt(0)-97+13)%26);
return String.fromCharCode(rotated);
}
"uryyb, jbeyq!".replace(/[a-z]/g,r);
=> "hello, world!"
<section>
<h1>code</h1>
<h2><a target="_blank" href="https://github.com/aronatkins/cc/">
made this
</a></h2>
</section>
instructions to solve a problem