Simple Sparkline using SVG Path and D3.js09 Aug 2011
Here are links to the code and working example:
To make the size more applicable to inline use as a sparkline decrease the ranges:
var x = d3.scale.linear().domain([0, 10]).range([0, 20]);
var y = d3.scale.linear().domain([0, 10]).range([0, 10]);
UPDATE: I added another version that shows animations with transformations and transitions.