---
id: 587d7faa367417b2b2512bd6
title: Add a Tooltip to a D3 Element
required:
- src: 'https://cdnjs.cloudflare.com/ajax/libs/d3/4.3.0/d3.min.js'
challengeType: 6
---
## 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.
## Tests
```yml
tests:
- text: Your code should have 9 title elements.
testString: assert($('title').length == 9, 'Your code should have 9 title elements.');
- text: The first title element should have tooltip text of 12.
testString: assert($('title').eq(0).text() == '12', 'The first title element should have tooltip text of 12.');
- text: The second title element should have tooltip text of 31.
testString: assert($('title').eq(1).text() == '31', 'The second title element should have tooltip text of 31.');
- text: The third title element should have tooltip text of 22.
testString: assert($('title').eq(2).text() == '22', 'The third title element should have tooltip text of 22.');
- text: The fourth title element should have tooltip text of 17.
testString: assert($('title').eq(3).text() == '17', 'The fourth title element should have tooltip text of 17.');
- text: The fifth title element should have tooltip text of 25.
testString: assert($('title').eq(4).text() == '25', 'The fifth title element should have tooltip text of 25.');
- text: The sixth title element should have tooltip text of 18.
testString: assert($('title').eq(5).text() == '18', 'The sixth title element should have tooltip text of 18.');
- text: The seventh title element should have tooltip text of 29.
testString: assert($('title').eq(6).text() == '29', 'The seventh title element should have tooltip text of 29.');
- text: The eighth title element should have tooltip text of 14.
testString: assert($('title').eq(7).text() == '14', 'The eighth title element should have tooltip text of 14.');
- text: The ninth title element should have tooltip text of 9.
testString: assert($('title').eq(8).text() == '9', 'The ninth title element should have tooltip text of 9.');
```
## Challenge Seed
## Solution
```js
// solution required
```