19 - Add a Hover Effect to a D3 Element - Data Visualization with D3 - freeCodeCamp Tutorial

We can use hover effects to update the styling of our elements using the :hover CSS pseudo-class.

Link to challenge : https://www.freecodecamp.org/learn/data-visualization/data-visualization-with-d3/add-a-hover-effect-to-a-d3-element Concepts: Hover The :hover CSS pseudo-class matches when the user interacts with an element with a pointing device, but does not necessarily activate it. It is generally triggered when the user hovers over an element with the cursor (mouse pointer). https://developer.mozilla.org/en-US/docs/Web/CSS/:hover

selection.attr(name[, value]) If a value is specified, sets the attribute with the specified name to the specified value on the selected elements and returns this selection. If the value is a constant, all elements are given the same attribute value; otherwise, if the value is a function, it is evaluated for each selected element, in order, being passed the current datum (d), the current index (i), and the current group (nodes), with this as the current DOM element (nodes[i]). The function’s return value is then used to set each element’s attribute. A null value will remove the specified attribute. If a value is not specified, returns the current value of the specified attribute for the first (non-null) element in the selection. This is generally useful only if you know that the selection contains exactly one element. https://github.com/d3/d3-selection/blob/v1.4.1/README.md#selection_attr -————————————————————————————————————- D3.js (also known as D3, short for Data-Driven Documents) is a JavaScript library for producing dynamic, interactive data visualizations in web browsers. It makes use of Scalable Vector Graphics (SVG), HTML5, and Cascading Style Sheets (CSS) standards.

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