To make the previous and next buttons disabled on the first page and last page, add these callbacks inside the load engine function before viewer init:
viewer.callback.Register("PostPageChange", hidePrevNext);
viewer.callback.Register("PostViewerInit", hidePrevNext);
add this function after the load engine function:
function hidePrevNext()
{
if (RVViewers[0].DisplayMode == "double")
{
if (RVKernel.features.StartDPS == true && (RVViewers[0].pages.current_page == 0 || RVViewers[0].pages.current_page == 1))
{
$('#toolbar_prev_btn').css('display', 'none');
$('#toolbar_next_btn').css('display', 'block');
}
else if (RVKernel.features.StartDPS == false && RVViewers[0].pages.current_page == 0)
{
$('#toolbar_prev_btn').css('display', 'none');
$('#toolbar_next_btn').css('display', 'block');
$('#leftpage').html(zeropage);
}
if ((RVKernel.features.StartDPS == true) && (RVViewers[0].pages.current_page == RVViewers[0].pages.count) && (RVViewers[0].pages.count % 2 == 0))
{
$('#toolbar_next_btn').css('display', 'none');
$('#toolbar_prev_btn').css('display', 'block');
}
else if((RVKernel.features.StartDPS == true) && (RVViewers[0].pages.current_page == RVViewers[0].pages.count) && (RVViewers[0].pages.count % 2 != 0))
{
$('#toolbar_next_btn').css('display', 'none');
$('#toolbar_prev_btn').css('display', 'block');
$('#topDiv #BackpageContent').html(backpage);
}
if(RVViewers[0].pages.current_page > 1 && RVViewers[0].pages.current_page < RVViewers[0].pages.count)
{
$('#toolbar_prev_btn').css('display', 'block');
$('#toolbar_next_btn').css('display', 'block');
resizetoolbar();
}
}
else if (RVViewers[0].DisplayMode == "single")
{
if (RVViewers[0].pages.current_page == 1)
{
$('#toolbar_prev_btn').css('display', 'none');
$('#toolbar_next_btn').css('display', 'block');
}
else if (RVViewers[0].pages.current_page == RVViewers[0].pages.count)
{
$('#toolbar_next_btn').css('display', 'none');
$('#toolbar_prev_btn').css({'top': RVKernel.coords.winh / 2, 'display': 'block'})
}
else
{
$('#toolbar_prev_btn').css('display', 'block');
$('#toolbar_next_btn').css('display', 'block');
resizetoolbar();
}
}
};
This handles single and double viewers.