Pyjamas

It allows writing web applications in Python, which is more suitable performance-wise for medium to large applications.

The AJAX library takes care of all the browser interoperability issues on your behalf, leaving you free to focus on application development instead of learning all the "usual" browser incompatibilities.

Features:

• pyjs - translates Python code to Javascript by walking the Python abstract syntax tree and generating Javascript.
• pyjslib - library of custom objects that implement methods such as append
• UI widgets as well as a library for DOM manipulation
• The overall translation of individual components is managed by build which also creates the necessary boilerplate code.

What is new in this release:

• Enabling of asynchronous module loading (previously present in the 0.5 pyjamas release).
• Adding HTML5-compliant drag-and-drop support (both native as well as emulated, so that older browsers appear to have HTML5-style drag-and-drop).
• Fixing a long-standing bug with DialogBox (still present in GWT) related to mouse events being lost.
• Addition of an "auto-build" option - based on file-monitoring - to pyjsbuild.
• Addition of oninput and onpropertychange event support, as well as DOM.createTextNode.

What is new in version 0.7:

• The addition of generators (support for yield, by rewriting the function so that it can be re-called and continue from the previous state); the rewriting allows all browsers (not just firefox - the only browser with a javascript-native "yield" feature) to appear to have python "yield" functionality;
• The beginnings of decorators support, and full support for properties, with the addition of property();
• Some dramatic performance improvements due to a rewrite of for-loops;
• Improved support for import syntax (from . import module);
• The addition of a built-in AST parser, use of which allows python 2.4 to compile programs with python 2.5 / 2.6 syntax into JavaScript;
• Addition of int and long types, and support for operator functions, so that e.g list multiplication by numbers and list addition now work, along with coercion between int, float and long types, and support for floating point exceptions including raising ZeroDivisionError;

What is new in version 0.4p1:

• Significant bugs fixed include HorizontalPanel's remove() function, SimplePanel's clear() function, and sprintf with multiple arguments ("%s %d" % ("hello", 2) will now work)
• Dialog Box now has modal functionality
• HorizontalSplitPanel has been added, although both the horizontal and vertical panels operate correctly on Mozilla-based browsers, but Safari and IE need volunteers to work on them.