<div id = "user" data-uid = "12345" data-uname = "极客世界" > </div>

// 使用getAttribute获取 data- 属性
var user = document . getElementById ( 'user' ) ;
var userName = plant . getAttribute ( 'data-uname' ) ; // userName = '极客世界'
var userId = plant . getAttribute ( 'data-uid' ) ; // userId = '12345'

// 使用setAttribute设置 data- 属性
user . setAttribute ( 'data-site' , 'https://www.ogeek.net' ) ;

<div id = "user" uid = "12345" uname = "极客世界" > </div>
<script>
// 使用getAttribute获取 data- 属性
var user = document . getElementById ( 'user' ) ;
var userName = plant . getAttribute ( 'uname' ) ; // userName = '极客世界'
var userId = plant . getAttribute ( 'uid' ) ; // userId = '12345'

// 使用setAttribute设置 data- 属性
user . setAttribute ( 'site' , 'https://www.ogeek.net' ) ;
</script>

<div id="user" data-id="1234567890" data-name="极客世界" data-date-of-birth>码头</div>
<script type="text/javascript">
var el = document.querySelector('#user');
console.log(el.id); // 'user'
console.log(el.dataset);//一个DOMStringMap
console.log(el.dataset.id); // '1234567890'
console.log(el.dataset.name); // '极客世界'
console.log(el.dataset.dateOfBirth); // ''
el.dataset.dateOfBirth = '1985-01-05'; // 设置data-date-of-birth的值.
console.log('someDataAttr' in el.dataset);//false
el.dataset.someDataAttr = 'mydata';
console.log('someDataAttr' in el.dataset);//true
</script>

// 选择所有包含 'data-flowering' 属性的元素
document . querySelectorAll ( '[data-flowering]' ) ;

// 选择所有包含 'data-text-colour' 属性值为red的元素
document . querySelectorAll ( '[data-text-colour="red"]' ) ;

<style type ="text/css">
.user {
width : 256px ;
height : 200px ;
}

.user[data-name='feiwen'] {
color : brown
}

.user[data-name='css'] {
color : red
}
</style>
<div class = "user" data-id = "123" data-name = "feiwen" > 1 </div>
<div class = "user" data-id = "124" data-name = "css" > 码头 </div>