onBeforePageChange

fires before the page is changed

void onBeforePageChange(number new_page,number old_page);

new_page	number	the index of the new page
old_page	number	the index of the changed page

Example

pager:{
    container:"paging_here",
    size:10,
    group:5,
    on:{
        onBeforePageChange:function(new_page, old_page){
            console.log(new_page, old_page)
    }}
}