function changeTab(id1, id2, id3, td)
{
    sh1 = document.getElementById('tabbed_block_' + id1);
    sh2 = document.getElementById('tabbed_block_' + id2);
    sh3 = document.getElementById('tabbed_block_' + id3);

    sh1.className = '';
    sh2.className = 'none_visible';
    sh3.className = 'none_visible';

    td.parentNode.className = 'active';
    t2 = document.getElementById('tab' + id2);
    t3 = document.getElementById('tab' + id3);
    t2.className = 'none_active';
    t3.className = 'none_active';
}

function inc_page (elem_name, pages)
{
    active_page = document.getElementById(elem_name).value;
    if (active_page < pages)
        document.getElementById(elem_name).value = parseInt(active_page) + 1;
}

function dec_page (elem_name, pages)
{
    active_page = document.getElementById(elem_name).value;
    if (active_page > 1)
        document.getElementById(elem_name).value = parseInt(active_page) - 1;
}

function inc(f)
{
    eval('var numb = document.forms.' + f + '.num;');
    l = parseInt(numb.value);

    eval('var input = document.forms.' + f + '.page;');
    n = input.value;

    if (!isNaN(n))
    {
        if (n < l)
            input.value = parseInt(n) + 1;
    }
    else 
        input.value = 1;
}

function dec(f)
{
    eval('var numb = document.forms.' + f + '.num;');
    l = parseInt(numb.value);

    eval('var input = document.forms.' + f + '.page;');
    n = input.value;
    
    if (!isNaN(n))
    {
        if (n > 1)
            input.value = parseInt(n) - 1;
    }
    else 
        input.value = 1;
    
}