let main_panel_buffer = null;

function show(file)
{
    if (main_panel_buffer == null) main_panel_buffer = document.getElementById("main_panel").innerHTML;

    $.ajax
    ({
        url: "./res/forum/" + file + ".html",
        dataType: "html",
        success: function(data)
        {
            $("#main_panel").html(main_panel_buffer + data);
        }
    });
}