// Перехватываем событие
document.onkeydown = NavigateThrough;
function NavigateThrough (event)
{
    if (window.event) event = window.event;

    if (event.ctrlKey)
    {
        var link = null;
        var href = null;
        switch (event.keyCode ? event.keyCode : event.which ? event.which : null)
          {
            case 0x27:
                link = document.getElementById ('NextLink');
                break;
            case 0x25:
                link = document.getElementById ('PrevLink');
        }

           if (link && link.href) document.location = link.href;
        if (href) document.location = href;
    }            
}