We came across some interesting behaviour while building a charting application with HTML, CSS and jQuery. When it came to animating the individual bars of the charts that we were generating the height would always grow downwards! As bizarre as this behaviour seemed fixing it proved to be relatively straightforward.
Firstly, we needed to ensure that the parent container for the div element to be animated was set with a rule of position:relative.
Then we declared a CSS rule of position:absolute and bottom:0 on the div element to be animated.
As the div element is now positioned absolutely from the bottom of the container it has nowhere to vertically increase but upwards.
When we ran the animations, after making these changes, the heights of the bars in our dynamically generated charts were vertically increasing upwards and not downwards - exactly the behaviour we wanted to see!