Take a look at TeeChart Javascript too.
Download it here: http://www.steema.com/download/html5
Find the online demos here:
http://www.steema.com/files/public/teechart/html5/v2012.06.1.1/demos/
- mixed line graphs and column graphs
Supported. Just add the series and some values.
- line graphs have to be stepped (no interpolation)
Supported. The Line series can be smoothed, but it isn't by default:
http://www.steema.com/files/public/teechart/html5/v2012.06.1.1/demos/series/line/linepoint.htm
- column charts must grow downwards from the top of the chart
Supported. You can just invert the left axis. In the following example there's a checkbox for it:
http://www.steema.com/files/public/teechart/html5/v2012.06.1.1/demos/series/bar/bar.htm
Supported. Find here an example:
http://www.steema.com/files/public/teechart/html5/v2012.06.1.1/demos/axes/multiple_axes.htm
Supported. Draw the rectangle with the left mouse button (from top-left to bottom-right) to zoom in the drawn area. Draw the rectangle on the other direction to zoom out (from bottom-right to top-left). Scroll dragging with the right mouse button.
If you find a problem with any of them, don't hesitate to let us know.