A copy of the JavaScript functions in the head element:

// sample-1-onsubmit.js
// This sample shows processing onsubmit of a form

// on load of the body
function loaded()
  {
  // reset the input text data
  current_input_text_object = document.getElementById("control1");
  current_input_text_object.value = null;  

  // reset radio button
  current_radio_button_array = document.getElementsByName("age");
  var checked = false;
  for ( var i = 0; i < current_radio_button_array.length ; i++ )
    {
    current_radio_button_array[i].checked = false;
    }

  // reset select list
  var pet_selection_list  = document.getElementById("petSelectionElement");
  pet_selection_list.selectedIndex = -1;

  }

// form onsubmit handler
function onsubmit_function(current_form)
  {
  var rc = true;

  // test for empty input text area
  current_input_text_object = document.getElementById("control1");
  if ( current_input_text_object.value == null || current_input_text_object.value == "" )
    { 
    alert("Pet name must be entered"); 
    rc=false;
    }

  // test for no radio button checked
  current_radio_button_array = document.getElementsByName("age");
  var checked = false;
  for ( var i = 0; i < current_radio_button_array.length ; i++ )
    {
    if ( current_radio_button_array[i].checked )
      checked = true;
    }
  if ( ! checked )
    { 
    alert("Pet age must be selected");
    rc=false;
    }

  // test for no option selected
  var pet_selection_list_element  = document.getElementById("petSelectionElement");
  if (pet_selection_list_element.selectedIndex < 0 )
    {
    alert("Type of pet must be selected");
    rc=false;
    }

  return rc;
  }