The JS9 display has a default width and height of 512x512. You can change this by adding data-width and data-height attributes to the divs. For example, to create a display of size 256x256, use:
    <div class="JS9" data-width="256px" data-height="256px">
    
    The data-width and data-height attributes can be
    applied to other JS9 divs, such as the menubar. For smaller menubars,
    make sure you specify a height value as well:
    
    <div class="JS9Menubar" id="JS9-256_Menubar" data-width="256px" data-height="54px">
    
    For smaller JS9 displays, you can change the style of the Menubar
    to "mac": the File, Edit and View menus will
    be displayed on the left side of the menubar and the Help
    menu on the right.  The other main menus are displayed as
    sub-menus within the View menu.