93 lines
2.1 KiB
Markdown
93 lines
2.1 KiB
Markdown
---
|
|
id: 587d7faa367417b2b2512bd4
|
|
title: Add a Hover Effect to a D3 Element
|
|
challengeType: 6
|
|
---
|
|
|
|
## Description
|
|
<section id='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 <code>attr()</code> method. Then the <code>:hover</code> pseudo-class for your new class holds the style rules for any hover effects.
|
|
</section>
|
|
|
|
## Instructions
|
|
<section id='instructions'>
|
|
Use the <code>attr()</code> method to add a class of <code>bar</code> to all the <code>rect</code> elements. This changes the <code>fill</code> color of the bar to brown when you mouse over it.
|
|
</section>
|
|
|
|
## Tests
|
|
<section id='tests'>
|
|
|
|
```yml
|
|
tests:
|
|
- text: Your <code>rect</code> elements should have a class of <code>bar</code>.
|
|
testString: assert($('rect').attr('class') == "bar", 'Your <code>rect</code> elements should have a class of <code>bar</code>.');
|
|
|
|
```
|
|
|
|
</section>
|
|
|
|
## Challenge Seed
|
|
<section id='challengeSeed'>
|
|
|
|
<div id='html-seed'>
|
|
|
|
```html
|
|
<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>
|
|
```
|
|
|
|
</div>
|
|
|
|
|
|
|
|
</section>
|
|
|
|
## Solution
|
|
<section id='solution'>
|
|
|
|
```js
|
|
// solution required
|
|
```
|
|
</section>
|