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freeCodeCamp/curriculum/challenges/english/04-data-visualization/data-visualization-with-d3/add-a-tooltip-to-a-d3-element.md
Nicholas Carrigan (he/him) 16e420021c chore: audit data visualisation challenges (#41336)
* chore(learn): audit d3 projects

* chore: audit data vis

* chore: audit json apis

* Update curriculum/challenges/english/04-data-visualization/data-visualization-projects/visualize-data-with-a-scatterplot-graph.md

Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com>

* fix: apply suggestions

Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com>

* fix: no colour backticks

Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com>
Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com>

* Update curriculum/challenges/english/04-data-visualization/json-apis-and-ajax/get-geolocation-data-to-find-a-users-gps-coordinates.md

Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com>

Co-authored-by: Shaun Hamilton <51722130+ShaunSHamilton@users.noreply.github.com>
Co-authored-by: Randell Dawson <5313213+RandellDawson@users.noreply.github.com>
2021-03-05 12:25:29 -07:00

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Markdown

---
id: 587d7faa367417b2b2512bd6
title: Add a Tooltip to a D3 Element
challengeType: 6
forumTopicId: 301470
dashedName: add-a-tooltip-to-a-d3-element
---
# --description--
A tooltip shows more information about an item on a page when the user hovers over that item. There are several ways to add a tooltip to a visualization, this challenge uses the SVG `title` element.
`title` pairs with the `text()` method to dynamically add data to the bars.
# --instructions--
Append a `title` element under each `rect` node. Then call the `text()` method with a callback function so the text displays the data value.
# --hints--
Your code should have 9 `title` elements.
```js
assert($('title').length == 9);
```
The first `title` element should have tooltip text of `12`.
```js
assert($('title').eq(0).text() == '12');
```
The second `title` element should have tooltip text of `31`.
```js
assert($('title').eq(1).text() == '31');
```
The third `title` element should have tooltip text of `22`.
```js
assert($('title').eq(2).text() == '22');
```
The fourth `title` element should have tooltip text of `17`.
```js
assert($('title').eq(3).text() == '17');
```
The fifth `title` element should have tooltip text of `25`.
```js
assert($('title').eq(4).text() == '25');
```
The sixth `title` element should have tooltip text of `18`.
```js
assert($('title').eq(5).text() == '18');
```
The seventh `title` element should have tooltip text of `29`.
```js
assert($('title').eq(6).text() == '29');
```
The eighth `title` element should have tooltip text of `14`.
```js
assert($('title').eq(7).text() == '14');
```
The ninth `title` element should have tooltip text of `9`.
```js
assert($('title').eq(8).text() == '9');
```
# --seed--
## --seed-contents--
```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) => d * 3)
.attr("fill", "navy")
.attr("class", "bar")
// 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 - (d * 3 + 3))
</script>
</body>
```
# --solutions--
```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) => d * 3)
.attr("fill", "navy")
.attr("class", "bar")
.append("title")
.text((d) => d)
svg.selectAll("text")
.data(dataset)
.enter()
.append("text")
.text((d) => d)
.attr("x", (d, i) => i * 30)
.attr("y", (d, i) => h - (d * 3 + 3))
</script>
</body>
```