HTML form created using google scripts
See demo here: https://goo.gl/XkQFct
And result here: https://goo.gl/vmeqMt
Credits to:
Alexander Ivanov http://gdriveru.blogspot.com/2015/02/FILEUPLOAD.html
Amit Agarwal https://ctrlq.org/code/19747-google-forms-upload-files
Dax Kieran at subtlepatterns.com https://www.toptal.com/designers/subtlepatterns/triangular/
Osvaldas Valutis http://tympanus.net/codrops/2015/09/15/styling-customizing-file-inputs-smart-way/