SmoWeb is a web platform for performing numerical computations and simulations. You could check it out on http://platform.sysmoltd.com
It is written in Python (for the server side) and JavaScript/AngularJS (for the client side) and integrates with a number of third party libraries for numerical computations (NumPy, SciPy, h5py, assimulo, SUNDIALS collections, CoolProp).
Each model is a single page application, entirely defined in a declarative way in Python. There are numerical, boolean and choices input fields. The results can be displayed as numbers, graphs, tables and MatPlotLib-generated plots.