var userLabel;
var userName;
var loginForm;
var els;
var fields;

if (document.getElementById) {
  userLabel = document.getElementById("user_label");
  userName = document.getElementById("username");
  loginForm = document.getElementById("login_form");
}
else if (document.all) {
  userLabel = document.all["user_label"];
  userName = document.all["username"];
  loginForm = document.all["login_form"];
}

if (user == "s") {
  userLabel.innerHTML = "Email";
  userName.setAttribute("title", "Email");
}
else {
  userLabel.innerHTML = "Username";
  userName.setAttribute("title", "Username");
}

els = loginForm.elements;
fields = ["username", "password"]

/**
 *  On-submit event handler to check for blank fields.
 *
 *  @type boolean
 */
loginForm.onsubmit = function()
{
  for (var i = 0; i < fields.length; i++) {
    if (els[fields[i]].value == "" || !(/\S+/.test(els[fields[i]].value))) {
      return false;
    }
  }
  return true;
};