Fully client side Chinese Character Practice Sheet generator: http://robbertbrak.com/chinese-character-sheets/.
Uses the fontkit branch of pdfkit, kindly packaged by fzcs for npm.
Note that I commented out most of the registered formats in fontkit/index.js to keep the filesize of the javascript bundle within reason.
The font is based on the freely available AR PL UKai font collection, converted from TTC to TTF with FontForge.
The HSK word lists were adapted from http://www.hskhsk.com/word-lists.html.