renderHorizontalBars script operation
Return an HTML table to display horizontal
bars - anHeights[i] should have the length of the i-th bar and asLabels[i]
the tooltip for the i-th bar
renderVerticalBars script operation
Return an HTML table to display vertical
bars - anHeights[i] should have the length of the i-th column and asLabels[i]
the tooltip for the i-th column