/**
  * Checks/unchecks all options of a <select> element
  *
  * @param   string   the form name
  * @param   string   the element name
  * @param   boolean  whether to check or to uncheck the element
  *
  * @return  boolean  always true
  */
function setSelectOptions(the_form, the_select, do_check)
{
    var selectObject = document.forms[the_form].elements[the_select];
    var selectCount  = selectObject.length;

    for (var i = 0; i < selectCount; i++) {
        selectObject.options[i].selected = do_check;
    } // end for

    return true;
} // end of the 'setSelectOptions()' function