Is there possible to load a mapfile file from a client to a server running a Mapserver? e.g. http://server/cgi-bin/mapserv?**map=**client/example/htdocs/example1-1.map&layer=states&mode=map
No. You may create a form for file upload from the browser, but you need server side script to process uploaded data or you can use ftp/scp to upload files to the server.