function initialize_navigation() {
    // initialize rootnavigation position
    $('root_navigation_button').src= 'templates/artistpool/img/buttons/root/' + _get_root_navigation_button_position_by_index(_get_current_navigation_index('root')) + '.jpg'; 
    
    $$('ul.root-navigation li a').each(function(element, index) {
        element.onmouseover = function() { 
            $('root_navigation_button').src= 'templates/artistpool/img/buttons/root/' + _get_root_navigation_button_position_by_index(index) + '.jpg'; 
        }
        element.onmouseout = function() { 
            $('root_navigation_button').src= 'templates/artistpool/img/buttons/root/' + _get_root_navigation_button_position_by_index(_get_current_navigation_index('root')) + '.jpg'; 
        }
        
    });
    
    // initialize subnavigation position
    //alert(_get_root_navigation_button_position_by_index(_get_current_navigation_index('sub')));
    $('sub_navigation_button').src= 'templates/artistpool/img/buttons/sub/' + _get_sub_navigation_button_position_by_index(_get_current_navigation_index('sub')) + '.jpg'; 
    
    $$('ul.sub-navigation li a').each(function(element, index) {
        element.onmouseover = function() { 
            $('sub_navigation_button').src= 'templates/artistpool/img/buttons/sub/' + _get_sub_navigation_button_position_by_index(index) + '.jpg'; 
        }
        element.onmouseout = function() { 
            $('sub_navigation_button').src= 'templates/artistpool/img/buttons/sub/' + _get_sub_navigation_button_position_by_index(_get_current_navigation_index('sub')) + '.jpg'; 
        }
        
    });
}


function _get_current_navigation_index(navigation) {
    var index_return = 0;
    $$('ul.' + navigation + '-navigation li').each(function(element, index) {
        if (element.className.indexOf("current") != -1) {
            index_return = index;
            return index;
        }
    });
    return index_return;
}

function _get_root_navigation_button_position_by_index(index) {
        var button_position = 1;
        if (index == 0) { button_position = 3; }
        if (index == 1) { button_position = 3; }
        if (index == 2) { button_position = 5; }
        if (index == 3) { button_position = 6; }
        if (index == 4) { button_position = 7; }
        if (index == 5) { button_position = 9; }
        if (index == 6) { button_position = 11; }
        if (index == 7) { button_position = 12; }
        if (index == 8) { button_position = 14; }
        if (index == 9) { button_position = 15; }
        return button_position;
}


function _get_sub_navigation_button_position_by_index(index) {
        return (index + 2);
}