2018-10-10 18:03:03 -04:00
|
|
|
---
|
|
|
|
|
id: 587d7fa7367417b2b2512bc8
|
2020-12-16 00:37:30 -07:00
|
|
|
title: 用 D3 添加 Class
|
2018-10-10 18:03:03 -04:00
|
|
|
challengeType: 6
|
2020-09-18 00:13:05 +08:00
|
|
|
forumTopicId: 301473
|
2021-01-13 03:31:00 +01:00
|
|
|
dashedName: add-classes-with-d3
|
2018-10-10 18:03:03 -04:00
|
|
|
---
|
|
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
# --description--
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
即使对小型 app 来说在 HTML 元素中大量使用内联样式表也十分难以管理。更方便的是给元素添加遵守 CSS 规则的类。D3 中的 `attr()` 方法可以给元素添加任何 HTML 属性，包括类名称。
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
`attr()` 方法和 `style()` 的使用方法一样。它以逗号分隔的键值对为参数使用回调函数。这里是一个给选中元素添加类名为 "container" 的例子：`selection.attr("class", "container");`
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
注意当 "container" 元素改变或者添加一个 class 时，"class" 参数会保持不变。
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
# --instructions--
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
在编辑器中添加 `attr()` 方法，给 `div` 元素添加类名 `bar`。
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
# --hints--
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
你的 `div`元素应该有一个`bar` 类。
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
```js
|
|
|
|
|
assert($('div').attr('class') == 'bar');
|
2018-10-10 18:03:03 -04:00
|
|
|
```
|
|
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
你应该使用 `attr()` 方法。
|
2018-10-10 18:03:03 -04:00
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
```js
|
|
|
|
|
assert(code.match(/\.attr/g));
|
2018-10-10 18:03:03 -04:00
|
|
|
```
|
2020-08-13 17:24:35 +02:00
|
|
|
|
2021-01-13 03:31:00 +01:00
|
|
|
# --seed--
|
|
|
|
|
|
|
|
|
|
## --seed-contents--
|
|
|
|
|
|
|
|
|
|
```html
|
|
|
|
|
<style>
|
|
|
|
|
.bar {
|
|
|
|
|
width: 25px;
|
|
|
|
|
height: 100px;
|
|
|
|
|
display: inline-block;
|
|
|
|
|
background-color: blue;
|
|
|
|
|
}
|
|
|
|
|
</style>
|
|
|
|
|
<body>
|
|
|
|
|
<script>
|
|
|
|
|
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
|
|
|
|
|
|
|
|
|
|
d3.select("body").selectAll("div")
|
|
|
|
|
.data(dataset)
|
|
|
|
|
.enter()
|
|
|
|
|
.append("div")
|
|
|
|
|
// Add your code below this line
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
// Add your code above this line
|
|
|
|
|
</script>
|
|
|
|
|
</body>
|
|
|
|
|
```
|
|
|
|
|
|
2020-12-16 00:37:30 -07:00
|
|
|
# --solutions--
|
|
|
|
|
|
2021-01-13 03:31:00 +01:00
|
|
|
```html
|
|
|
|
|
<style>
|
|
|
|
|
.bar {
|
|
|
|
|
width: 25px;
|
|
|
|
|
height: 100px;
|
|
|
|
|
display: inline-block;
|
|
|
|
|
background-color: blue;
|
|
|
|
|
}
|
|
|
|
|
</style>
|
|
|
|
|
<body>
|
|
|
|
|
<script>
|
|
|
|
|
const dataset = [12, 31, 22, 17, 25, 18, 29, 14, 9];
|
|
|
|
|
|
|
|
|
|
d3.select("body").selectAll("div")
|
|
|
|
|
.data(dataset)
|
|
|
|
|
.enter()
|
|
|
|
|
.append("div")
|
|
|
|
|
// Add your code below this line
|
|
|
|
|
.attr("class","bar");
|
|
|
|
|
// Add your code above this line
|
|
|
|
|
</script>
|
|
|
|
|
</body>
|
|
|
|
|
```
|
