I will develop a web app that can recognize text using the smartphone camera. I saw on the web that exist a lot solution that can recognize text in a picture/stream video, but all this solution need to develop a native app. I want to recognize text by creating a little site in which I can do the following stuff:

1. Register myself


2. Access to the smartphone camera


3. Recognize text in a shot


4. Show the letters recognized in a simply label


5. Save this letters in a remote database associated to my account

Anyone knows a way to recognize letters without taking a pic and without do a native app?
On the web I found tesseract ocr, but I'm not sure that I can use in a HTML5, CSS3 and javascript page. Does anyone used this library? In which mobile browser it works (Safari for iOS, browser for Android and Internet Explorer for Windows Phone 7/8)?