2.6 KiB
		
	
	
	
	
	
	
	
			
		
		
	
	
			2.6 KiB
		
	
	
	
	
	
	
	
id, title, challengeType, forumTopicId, dashedName
| id | title | challengeType | forumTopicId | dashedName | 
|---|---|---|---|---|
| 587d7faa367417b2b2512bd4 | Add a Hover Effect to a D3 Element | 6 | 301469 | add-a-hover-effect-to-a-d3-element | 
--description--
It's possible to add effects that highlight a bar when the user hovers over it with the mouse. So far, the styling for the rectangles is applied with the built-in D3 and SVG methods, but you can use CSS as well.
You set the CSS class on the SVG elements with the attr() method. Then the :hover pseudo-class for your new class holds the style rules for any hover effects.
--instructions--
Use the attr() method to add a class of bar to all the rect elements. This changes the fill color of the bar to brown when you mouse over it.
--hints--
Your rect elements should have a class of bar.
assert($('rect').attr('class') == 'bar');
--seed--
--seed-contents--
<style>
  .bar:hover {
    fill: brown;
  }
</style>
<body>
  <script>
    const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
    const w = 500;
    const h = 100;
    const svg = d3.select("body")
                  .append("svg")
                  .attr("width", w)
                  .attr("height", h);
    svg.selectAll("rect")
       .data(dataset)
       .enter()
       .append("rect")
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - 3 * d)
       .attr("width", 25)
       .attr("height", (d, i) => 3 * d)
       .attr("fill", "navy")
       // Add your code below this line
       // Add your code above this line
    svg.selectAll("text")
       .data(dataset)
       .enter()
       .append("text")
       .text((d) => d)
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - (3 * d) - 3);
  </script>
</body>
--solutions--
<style>
  .bar:hover {
    fill: brown;
  }
</style>
<body>
  <script>
    const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
    const w = 500;
    const h = 100;
    const svg = d3.select("body")
                  .append("svg")
                  .attr("width", w)
                  .attr("height", h);
    svg.selectAll("rect")
       .data(dataset)
       .enter()
       .append("rect")
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - 3 * d)
       .attr("width", 25)
       .attr("height", (d, i) => 3 * d)
       .attr("fill", "navy")
       // Add your code below this line
       .attr('class', 'bar')
       // Add your code above this line
    svg.selectAll("text")
       .data(dataset)
       .enter()
       .append("text")
       .text((d) => d)
       .attr("x", (d, i) => i * 30)
       .attr("y", (d, i) => h - (3 * d) - 3);
  </script>
</body>