function InitContent() {
    $('content').writeAttribute('class', 'book_content');
}

function InitBottomNav() {
    if (!$('TheBook') && $('ctl01_BottomNav'))
        $('ctl01_BottomNav').hide();
}

var _curPage = 0;

function SetNavJsHandler(id, isNext) {
    var link = $(id);
    if (link) {
        var nhref = link.readAttribute("nhref");
        if (nhref && nhref.length > 0)
            return;
            
        if (isNext)
            link.observe('click', function(e) { NextBookPage(); StopEvent(e); });
        else
            link.observe('click', function(e) { PrevBookPage(); StopEvent(e); });
        link.writeAttribute("nhref", link.readAttribute("href"));
        link.writeAttribute("href", "#");
    }
}

function StopEvent(e) {
    if (!e) var e = window.event;
    e.cancelBubble = true;
    if (e.stopPropagation) e.stopPropagation();
}

function ResetNavJsHanlder(id, isNext) {
    var link = $(id);
    if (link) {
        if (isNext)
            link.stopObserving('click', function() { NextBookPage(); return false; });
        else
            link.stopObserving('click', function() { PrevBookPage(); return false; });
        if (link.readAttribute("nhref")) {
            link.writeAttribute("href", link.readAttribute("nhref"));
            link.writeAttribute("nhref", "");
        }
    }
}

function PrevBookPage() {
    ChangeBookPage(_curPage - 1);
}
function NextBookPage() {
    ChangeBookPage(_curPage + 1);
}

function ChangeBookPage(page) {
    var table = $('TheBook');
    if (!table || table.rows.length < 2)
        return;

    SetNavJsHandler('ctl01_TopNavBack', false);
    SetNavJsHandler('ctl01_TopNavForward', true);
    SetNavJsHandler('ctl01_BottomNavBack', false);
    SetNavJsHandler('ctl01_BottomNavForward', true);

    if (page < 0) {
        ResetNavJsHanlder('ctl01_TopNavBack', false);
        ResetNavJsHanlder('ctl01_BottomNavBack', false);
    }
    if (page >= table.rows.length) {
        ResetNavJsHanlder('ctl01_TopNavForward', true);
        ResetNavJsHanlder('ctl01_BottomNavForward', true);
    }
    _curPage = page;
    
    DisplayPage();
}

function DisplayPage() {
    var table = $('TheBook');
    if (!table)
        return;

    if (_curPage < 0 || _curPage >= table.rows.length)
        return;
        
    for (var i = 0; i < table.rows.length; i++) {
        var elm = table.rows[i];
        elm.id = 'book_row_' + i;
        if (i == _curPage) {
            $(elm.id).writeAttribute("class", "selected");
        }
        else {
            $(elm.id).writeAttribute("class", "notselected");
        }
    }
}