This example shows an interactive scatterplot of the Iris dataset, where users can select which quantitative or categorical attributes to plot on the x- and y-axes via HTML dropdown menus built with the custom `menu` component. The visualization uses D3 version 6.7.0, rendering points as SVG circles that animate between positions using `transition` and `delay`, with axes updated via `axisBottom` and `axisLeft`. The code dynamically switches between `scaleLinear` for quantitative data and `scalePoint` for categorical data, and includes smooth enter-update-exit transitions for the circles.