Another important aspect which should be considered in the comparison is the support from community (i.e. # of users/developers/commits in last month, etc.) for that JS charting library. Although it is hard to gather this kind of information, I think it is the most valuable for the final decision.
|Chart types by category||HTML5 canvas capable (fallback method)||Size||GWT support||Dependency on other js libs||Mobile friendly||Level of interactiveness||License||Can incorporate custom graphics (background images, icons)||Largest Sites currently using||Project health (mailing list traffic, Stack Overflow questions)||Formats supported||Interesting features|
GWT Version - 3,6 Mb
|Yes||No||No||hovers and follows||ArcadiaCharts license||Yes||Latest realease Jan-13-2012||png||apply color and style, Axis types, CSV data import|
|Cubism.js||realtime series||Yes||78,5 Kb||No||D3||No||hovers and follows||Apache License||No||7 commits , 20 wiki messages in last month||scalable, effective (each pixel encodes a distinct point in time), data-source agnostic|
|D3||arc, polar area, gantt, timelines and timing, sankey, candlestick, data table, hypergraph||Yes||109 Kb||No||No||No||hovers and follows||BSD license||No||6 commits, 30 new wiki messages, 1796 search results and 179 new topics on stackoverflow in last month||a large number of solutions for data visualization|
|Dojo GFX||bar, line, pie, bubble, candleStick, area, scatter, high-low, column, stacked, clustered and spider||No||variable, from 31 Kb up to 3,7 Mb||Yes||No||Yes||hovers and follows||modified BSD license/ the Academic Free License version 2.1||No|| 16 search results on stackoverflow.
Books: Dojo: The Definitive Guide, Practical Dojo Projects, Learning Dojo, etc.
|supports gauges, openLayers maps and geo charting|
|dygraphs||area, bar, candlestick, line||Yes||69 Kb||No||No||Yes||hovers, follows and zooming||MIT||Yes||Integrated Space Weather Analysis System, Eutelsat, 10gen MongoDB Monitoring Service||34 search results and 1 new topics on stackoverflow in last month||png||Supports error bands around data series, can intelligently chart fractions, customizable click-through actions|
|Flot||bars, lines, points, filled areas, time series, pie, stacked charts any combinations of these, in the same plot and even on the same data series||Yes||core size is 37 Kb, plugins vary in size||Yes, gflot||jQuery||Yes, all iOS and most Android devices||legends, hovers and drilldowns, panning, zooming, mouse tracking, automatically redraw when window is resized||MIT/BSD||Yes||873 search results and 39 new topics on stackoverflow and 25 new topics on groups in last month
||jpg, png||using various symbols for points, multiple axis plotting prerendered images and many other|
|Flotr2||bar, line, candlestick, area, scatter, whisker, bubbles, timeline, time, pie, radar||Yes, (IE support with FlashCanvas and excanvas)||variable, from 31 Kb up to 656 Kb||No||No||Yes, built for performance and includes touch events / multi touch||select, zoom, pointer tracking, hovers, robust internal event system||MIT||Yes||10 earch results and 2 new topics on stackoverflow in last month||jpg, png||extensible plugin framework, tuned for performance. JSON api, programmable for interactivity|
|Google Chart Tools||pie, scatter, gauge, geo, combo, line, bar, area, candlestick||Yes||works on the principle "chart as service"||Yes||No||Yes||hovers and follows||Terms of Service.||No||135 search results and 8 new topics on stackoverflow in last month|
|Highcharts||line, spline, area, areaspline, column, bar, pie and scatter||No||311 Kb||Yes||No||Yes||hovers, follows and zooming||highcharts license||Yes||1001 search results and 118 new topics on stackoverflow in last month||jpg,png, pdf, svg||rich in its capabilities library|
|Humble Finance(library are no longer supported)||two 2d data sets which share an axis||Yes||up to 3.7 Mb||No||Prototype and Flotr||No||hovers, follows and zooming||MIT||No||3 search results on stackoverflow||this tool lends itself well to the display of financial data|
|Envision.js||real-time, timeSeries, finance, custom (fractal)||Yes||up to 1.3 Mb||No||Flotr2||No||hovers, follows and zooming||MIT||No||5 new topics on groups in last month||Allows you to create dynamic and interactive HTML5 visualizations|
|jqPlot||bar, line, area, xy, scatter, combo, pie, donut, column, logarithmic scale charts, time plot||Yes||variable. Core size is 172 Kb, with all additional plugins up to 493 Kb||No||jQuery||Yes. There are plugins for mobile support||hover, highlighting, legends, click to turn toggle series on/off, tooltips, etc||MIT/GPL v2||Yes||Wikimedia||active project with 73 forks.. 526 search results and 55 new topics on stackoverflow, 52 new topics on groups in last month||png||chart types like Mekko, bubble, pyramid, funnel and block charts. Ability to drag and drop points. Automatic trend line calculations|
|jQuery Sparklines||line, bar, tristate, discrete, pie charts, bullet graphs||No||up to 119 Kb||No||jQuery||No||form of tooltips, mouseover highlighting and click interaction||New BSD License||No||25 search results and 3 new topics on stackoverflow in last month||plugin for generate sparklines (small inline charts)|
|jQuery Visualize||bar, area, pie, line||Yes||24,2 Kb||No||jQuery||Yes||hovers and follows||MIT||Yes||32 search results on stackoverflow||visualize is one of the 12 enhancement-driven widgets that accompanies on the book Designing with Progressive Enhancement|
|milkchart||bar, line, scatter, column, pie, donut||Yes||Minified is at 25 Kb||No||Mootools||Yes||legends||MIT||No||8 search results on stackoverflow||png||simple and small. Takes a Table element or JSON data|
|RGraph||bar, bi-polar,line, pie, donut, Gantt, Funnel, Waterfall, gauge, progress bars, meter, radar, scatter radial scatter, rose||Yes||variable up to 830 Kb||No||No||Yes||tooltips, annotating, context, menus, resizing, zoom||RGraph license||Yes||Latest realease June-01-2012, 58 search results and 6 new topics on stackoverflow in last month||png||many interesting types of charts, good documentation|
|Rickshaw||area, lines, bars, scatterplot||No||variable up to 712 Kb||Yes||D3||No||renderers, legends, hovers, range selectors, etc.||MIT||No||9 search results and 2 new topics on stackoverflow in last month||works with real-time data|
|Timeplot||time series||No||161 Kb||Yes||No||No||hovers and follows||BSD||No||16 search results and 1 new topics on stackoverflow in last month||interactive time series plots and overlay Timeline event files over them|