@archeg,
You can bind mouse events to the chart-container(div) and get mouse coordinates in pixels, which you can convert to corresponding value along axis using convertPixelToValue as shown in this documentation page.
If this doesn’t fulfill your requirements, kindly create a JSFiddle with your use-case and share it with us so that we can look into the chart options being used, understand the scenario better and help you resolve.
—
Shashi Ranjan
Team CanvasJS