var  pr_1 = "mai";
var  pr_2 = "lto:";
var  login = "info";
var  at = "@";
var  s = "noclegi-pobierowo.pl";

var newLink=document.createElement('a');
newLink.setAttribute('href',pr_1+pr_2+login+at+s);
newLink.className='blank';

var linkText=document.createTextNode(login+at+s);
newLink.appendChild(linkText);
document.getElementById('email_adres').appendChild(newLink);