infra/roles/stable/etherpad/files/index.js

function customStart()
{
  //define your javascript here
  //jquery is available - except index.js
  //you can load extra scripts with $.getScript http://api.jquery.com/jQuery.getScript/
  function setRandomName() {
      document.getElementById("padname").value = randomPadName();
  }
  setRandomName();

}