Graham onedc or this
it will look for web_header - touch_header - mobile_header one problem for this is due to the way source works you need to add another function for each layer of directories that contain html pages
The files must be plain text and can contain anything except more xtscript

<!--parser:xtscript--> var $dev=<xt:get_device_template /> var $base=_header call source $file=/$dev$base call source $file=../$dev$base call source $file=../../$dev$base <!--/parser:xtscript-->