What is trackball and how to use trackball in the ejChart?

Trackball is an interactive feature in the jQuery Chart that is used to display details about a point in the Chart close to the current mouse location. Trackball displays a vertical line, marker, symbols like circle, star, etc., and tooltip at the point closest to the current mouse location for each series.

Trackball is available for only one point in each series when more than one series are present in the series collection.

Trackball is enabled by setting the visible property of the crosshair to true and the type property of the crosshair to trackball. It provides options to customize the trackball line and marker. Trackball displays crosshair labels in the axis when the visible property of the crosshairLabel is set to true in the horizontal axis.

The following code example illustrates this.

JS

$("#container").ejChart({
    crosshair: {
        visible: true,
        type: 'trackball',
        line: {
            color: 'transparent', 
        }
        . . . . . .
    }
    . . . . . . . .
    . . . . . . . .
});

The following screenshot displays the Chart with trackball. Trackball line is not visible in the screenshot because of setting transparent color to the trackball line.

JS Playground sample link: Chart Trackball