How to use:
1) click the icon with add-on toolbar, then it will generate a QRCode image for link of current tab at the center of page.
2) select some text in page, right click and select "Generate QRCode", then it will generate a QRCode Image for what you just select
3)use QRCode app within your smartphone to take a picture, decode QRCode image to text. You don't have a QRCode app? Just install one, like http://qrdroid.com/ (for android), itunes://itunes.apple.com/cn/app/er-wei-ma-kuai-pai/id483336864?mt=8 (for iphone/ipod touch/ipad)
this extension uses Google Chart API as code generator