Data renderers allow jqPlot to pull data from any external source (e.g. a function implementing an AJAX call). Simply assign the external source to the "dataRenderer" plot option. The only requirement on data renderers is that it must return a valid jqPlot data array.
Data renderers get passed options by the plot. The signiture for a data renderer is:
function(userData, plotObject, options) { ... return data; }
Where userData is whatever data was passed into the plot, plotObject is a reference back to the plot itself, and options are any options passed into the plots "dataRendererOption" option. The following example shows a more complicated example which uses ajax pulls data from an external json data source.