WebPrint
Print directly to printers using Javascript.
WebPrint is a fork of QZ-print: https://github.com/qzindustries/qz-print
It uses postMessage API and/or ajax calls to communicate with the Java applet. This differs from QZ-print, that uses Java Web Start and the Java deployment framework for communication.
The Java deployment framework is set to be removed in early 2015, I wanted to find another way to use QZ-print, which provides a seamless printing experience for web applications.
See an example.html/webprint.js for usage or click here for a live version of the example.
If WebPrint has helped with your project, please donate to support it's future development.
OS Compatability
The main Webprint applet (hosted here) is compatible with Windows, OSX and Linux.
Android support is provided via the Android app: https://github.com/micwallace/webprint-android NOTE: Serial and HTML printing is not currently supported on Android.
The javacript library will prompt you to install or open the correct applet if it is not running.
HTTPS usage
If you site uses HTTPS, requests to HTTP server are almost certainly blocked by default due to mixed-content restrictions. Thankfully, WebPrint uses an innovative solution to avoid this by using an intermediary browser tab/window and the postMessage API. This negates the need for end-users to change their browser settings. For an example on how to use this feature, see example.html in the project. Note that the example prints ESC/P formatted data which may not be compatible with all printers.
How this came about
Mid last year I developed an android applet that essentially accepts http requests and forwards them to the specified socket or network printer. https://github.com/micwallace/HttpSocketAdaptor
After a few months I found this solution stopped working due to stronger mixed-content restrictions in most browsers. Thanks to the postMessage API I was able to securely avoid these restrictions.
After that WebPrint was just a matter of time.
Thanks
A big thanks to the qz-print guys for allowing this project to happen and EJ Technologies for providing their excellent cross platform installer.
