var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";

function decode64(input) {
  var output = "";
  var chr1, chr2, chr3;
  var enc1, enc2, enc3, enc4;
  var i = 0;

  // remove all characters that are not A-Z, a-z, 0-9, +, /, or =
  input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

  do {
    enc1 = keyStr.indexOf(input.charAt(i++));
    enc2 = keyStr.indexOf(input.charAt(i++));
    enc3 = keyStr.indexOf(input.charAt(i++));
    enc4 = keyStr.indexOf(input.charAt(i++));

    chr1 = (enc1 << 2) | (enc2 >> 4);
    chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
    chr3 = ((enc3 & 3) << 6) | enc4;

    output = output + String.fromCharCode(chr1);

    if (enc3 != 64) {
      output = output + String.fromCharCode(chr2);
    }
    if (enc4 != 64) {
      output = output + String.fromCharCode(chr3);
    }
  } while (i < input.length);

  return output;
}

function convert_email_links(){
  doc = window.document;
  aEls = doc.getElementsByTagName('a');
  for(i=0;i<aEls.length;i++){
    a = aEls[i];
    if(a.href.match(/mailto\:[a-zA-Z0-9\=]+/)){
      email_b64 = a.getAttribute('href').replace(/mailto\:/, '');
      email = decode64(email_b64);
      a.setAttribute('href', 'mailto:' + email);
      a.firstChild.nodeValue = email;
    }
  }
}

window.onload = convert_email_links;