/*
	 Given the id of a form, gets all input and select elements and serializes
	 them into a query string.
	 Note: a bit heavier than the true core extensions, modifying Array and such!
	       Perhaps need a new .js file that's more appropriate?
*/
function serializeForm(form_element_id) {

	var form_element = document.getElementById(form_element_id);
	var input_elements = form_element.getElementsByTagName("input");
	var select_elements = form_element.getElementsByTagName("select");

	var serialized_form = "";

	for(var i=0; i < input_elements.length; i++) {
		if (serialized_form != "") { serialized_form += "&"; }
		serialized_form += input_elements[i].name + "=" + encodeURIComponent(input_elements[i].value);
	}

	for(var i=0; i < select_elements.length; i++) {
		if (serialized_form != "") { serialized_form += "&"; }
		var selected_index = select_elements[i].selectedIndex;
		var selected_value = select_elements[i].options[selected_index].value;
		serialized_form += select_elements[i].name + "=" + encodeURIComponent(selected_value);
	}
	return serialized_form;
}


/*
	quick & easy style updater
*/
function update_visibility(elem_id, new_visibility) {
	elem_to_update = document.getElementById(elem_id)
	if (elem_to_update) {
		elem_to_update.style.visibility = new_visibility;
	}
}

//********************* RADIO BUTTON-RELATED EXTENSIONS **********

/*
	Selects a given element as the current radio button option, given the id 
	or the element itself.
*/
function set_radio(radio_element) {
	radio_element = $(radio_element);
	radio_element.checked = true;
}

/*
	Sets a text field to the given value, or 0 by default.
*/
function clear_text(text_id, new_val) {
	element_to_clear = $(text_id)
	if (!new_val) { new_val = 0; }
	element_to_clear.value = new_val;
}

/*
	Attaches a numeric entry field to a radio button option; provides both 
	validation (with auto-correction) of the numeric entry field and also selects 
	the associated option whenever the value is set to a non-zero number...
*/
function associate_numeric_text_with_radio(text_element) {
	text_element = $(text_element);
	current_value = parseInt(text_element.value);
	
	// disallow non-numeric entry...
	if ( isNaN(current_value) ) { text_element.value = ''; return; }
	
	// ensure only proper integers entered into the text field:-)
	if (current_value.toString() != text_element.value) { text_element.value = current_value.toString(); }
	
	// don't change selection based on 0-valued number...
	if ( current_value == 0 ) { return; }

	// mark the associated radio choice after modifying the text value to a non-zero number...
	set_radio('rollover_fsa_has_balance');
}

//****************** ARRAY EXTENSIONS ********************
/*
	extend the Array object type with a useful little contains method.
*/
Array.prototype.contains = function(check_for) {
  for(var i=0; i < this.length; i++) {
    if (this[i] == check_for) {
      return true;
    }
  }
  return false;
}

Array.prototype.add_unique = function(array_to_add) {
  for(var i=0; i < array_to_add.length; i++) {
    if (!this.contains(array_to_add[i])) {
      this.push(array_to_add[i]);
    }
  }
}

Array.prototype.add_all = function(array_to_add) {
  for(var i=0; i < array_to_add.length; i++) {
    this.push(array_to_add[i]);
  }
}

Array.prototype.remove = function(index_to_remove) {
	for (var i=index_to_remove; i < this.length - 1; i++) {
		this[i] = this[i + 1];
	}
	this.length -= 1;
}

// a little helper method which returns a simple html list representing this array...
Array.prototype.html_list = function() {
	
	var list_elem = document.createElement('list');
	
	for (var i=0; i < this.length; i++) {
		var list_item_elem = document.createElement('li');
		list_item_elem.appendChild(document.createTextNode(this[i]));
		list_elem.appendChild(list_item_elem);
	}
	return list_elem;
}