MrShake - pastebin.com/qSTY96AP

gistfile1.js

window.addEvent('domready', function() {
  $('fullconfreg').addEvent('click', calculate);
  $('fullconfspouse').addEvent('click', calculate);
  $('fullconfregfirsttime').addEvent('click', calculate);
  $('intspeechticket').addEvent('click', calculate);
  $('evalticket').addEvent('click', calculate);
  $('fridinnerham').addEvent('click', calculate);
  $('fridinnerroastbeef').addEvent('click', calculate);
  $('fridinnerturkey').addEvent('click', calculate);
  $('satlunch').addEvent('click', calculate);
  $('satdinsteak').addEvent('click', calculate);
  $('satdinsalmon').addEvent('click', calculate);
  $('satdinveg').addEvent('click', calculate);


  function calculate() {
    if ( parseInt($('fullconfreg').value) > 0) {
      $('totalamount1_id').value = parseInt($('fullconfreg').value) * 15);

    if ( parseInt($('fullconfspouse').value) > 0) {
      $('totalamount2_id').value = parseInt($('fullconfspouse').value) * 5);

    if ( parseInt($('fullconfregfirsttime').value) > 0) {
      $('totalamount3_id').value = parseInt($('fullconfregfirsttime').value) * 5);

    if ( parseInt($('intspeechticket').value) > 0) {
      $('totalamount4_id').value = parseInt($('intspeechticket').value) * 5);

    if ( parseInt($('evalticket').value) > 0) {
      $('totalamount5_id').value = parseInt($('evalticket').value) * 15);

    if ( parseInt($('fridinnerham').value) > 0) {
      $('totalamount6_id').value = parseInt($('fridinnerham').value) * 5);

    if ( parseInt($('fridinnerroastbeef').value) > 0) {
      $('totalamount7_id').value = parseInt($('fridinnerroastbeef').value) * 5);

    if ( parseInt($('fridinnerturkey').value) > 0) {
      $('totalamount8_id').value = parseInt($('fridinnerturkey').value) * 5);

    if ( parseInt($('satlunch').value) > 0) {
      $('totalamount9_id').value = parseInt($('satlunch').value) * 5);

    if ( parseInt($('satdinsteak').value) > 0) {
      $('totalamount10_id').value = parseInt($('satdinsteak').value) * 5);

    if ( parseInt($('satdinsalmon').value) > 0) {
      $('totalamount11_id').value = parseInt($('satdinsalmon').value) * 5);

    if ( parseInt($('satdinveg').value) > 0) {
      $('totalamount12_id').value = parseInt($('satdinveg').value) * 5);

    var grandtotal = totalamount1_id + totalamount2_id + totalamount3_id + totalamount4_id + totalamount5_id + totalamount6_id 
                     + totalamount7_id + totalamount9_id + totalamount9_id + totalamount10_id + totalamount11_id + totalamount12_id;
}

  };
});

<input type=button value="click here" onClick='alert("This is a tesT")';    
style="color: black; background=royalblue;  font-size: 8pt; font-weight: bold">