[技術] 刮刮樂

刮刮卡範例
http://www.senamion.com/blog/jScratchcard.html

iphone沒有mouse down
http://stackoverflow.com/questions/9975352/javascript-html5-canvas-drawing-instead-of-dragging-scrolling-on-mobile-devic

控制canvas不動的範例
http://www.html5rocks.com/en/mobile/touch/
http://paulirish.com/demo/multi

html5 touch canvas
http://tenderlovingcode.com/blog/web-apps/html5-canvas-drawing-on-ipad/

html5 刮刮樂效果
http://beej.us/blog/data/html5-canvas-globalcompositeoperation/