Bar chart with D3.js
A bar chart displays the relative popularity of programming languages using percentage values from Stack Overflow's 2019 survey. The implementation uses D3 v5 with SVG rendering, constructing linear and band scales to position bars and axes while appending value labels to each bar. Hovering over a bar highlights it, dims other labels, and draws a dashed reference line that computes and displays the percentage divergence between the selected language and all others.