Find unique chars from string

<!DOCTYPE html>
<html>

  <head>
    <link rel="stylesheet" href="style.css">
    <script src="script.js"></script>
  </head>

  <body>
    <h1>Hello Plunker!</h1>
  </body>

</html>

// Code goes here

document.write("Unique characters in 'Joy George K' is ",uniq("Joy George K"));

function uniq(str) {
  return str.split('').filter(function(item, index, self) {
    return self.indexOf(item) == index;
  }).join('');
}

/* Styles go here */