/* ALL CODE COPYRIGHT ZEHN 2009 */

/* onFocus observations for username and password boxes */

document.observe("dom:loaded", function()
{ 
  // observe all form elements
  Event.observe($('login_username'), 'focus', function()
  {
    form_empty_value($('login_username'), "username");
  });
  Event.observe($('login_username'), 'blur', function()
  {
    form_fill_value($('login_username'), "username");
  });
  Event.observe($('login_password'), 'focus', function()
  {
    form_empty_value($('login_password'), "password");
  });
  Event.observe($('login_password'), 'blur', function()
  {
    form_fill_value($('login_password'), "password");
  });
});

// empties the value of the given form element, if its current value is string
function form_empty_value(element, string)
{
  if(element.value == string)
  {
    element.value = '';
  }
}

//assigns string to value of the given form element, if its current value is empty
function form_fill_value(element, string)
{
  if(element.value == '')
  {
    element.value = string;
  }
}