// An Object whose properties hold Arrays of OptionType/Value pairs
  var MAIN_OPTIONS = new Object();

  function update_MAIN_OPTIONS(sTargetFieldID, sTypeName, sOptionTypeValue){
    // create the MAIN_OPTIONS' object property that'll hold the array of type/value pairs for this set of options
    // as long as the property doesn't already exist.
    if (MAIN_OPTIONS[sTargetFieldID] == undefined){
      MAIN_OPTIONS[sTargetFieldID] = new Array();
    }

    // add the type/value pair to the array and an id, so we can directly update if needed.
    if (MAIN_OPTIONS[sTargetFieldID][sTypeName] == undefined){
      MAIN_OPTIONS[sTargetFieldID][MAIN_OPTIONS[sTargetFieldID].length] = sOptionTypeValue;
      MAIN_OPTIONS[sTargetFieldID][sTypeName] = new Array((MAIN_OPTIONS[sTargetFieldID].length-1),
      MAIN_OPTIONS[sTargetFieldID][MAIN_OPTIONS[sTargetFieldID].length-1]);
    } else {
    // directly update the type/value pair in the array.
      MAIN_OPTIONS[sTargetFieldID][sTypeName][1] = sOptionTypeValue;
      MAIN_OPTIONS[sTargetFieldID][MAIN_OPTIONS[sTargetFieldID][sTypeName][0]] = sOptionTypeValue;
    }
  }

  // Function for updating the hidden options field.
  function optionTypeValues(oSelectObj){
    // string for holding the select form element's name.
    var sTypeName = oSelectObj.name;

    // object ref which points to the related options hidden field.
    var oOptionTypeValues = eval("document.getElementById('mainForm').optionTypeValues_"+(sTypeName.split("_"))[1]);

    // string for holding the target field's ID.
    var sTargetFieldID = oOptionTypeValues.id;

    // string for holding the concatenated value of the optionTypePk and the optionPk.
    var sOptionTypeValue = (sTypeName.split("_"))[2] + "=" + oSelectObj[oSelectObj.selectedIndex].value;

    // update the MAIN_OPTIONS object to reflect additions or updates
    update_MAIN_OPTIONS(sTargetFieldID, sTypeName, sOptionTypeValue);

    // update the target field's value, for posting the data.
    oOptionTypeValues.value = MAIN_OPTIONS[sTargetFieldID].join(":");
  }