查询单个元素document.getElementById
示例
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
</ style >
</ head >
< body >
< ul id = "ul" >
< li id = "a" >油条</ li >
< li id = "b" >包子</ li >
< li id = "c" >米饺</ li >
< li id = "d" >< a >鱼粉</ a ></ li >
</ ul >
< script >
// 返回单一元素节点
var el = document.getElementById('a');
el.className='mycolor';
</ script >
</ body >
</ html >
|
按CSS查询一个 document.querySelector
按CSS查询
示例1 查询一个
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
.steam{
text-decoration: initial;
}
</ style >
</ head >
< body >
< ul id = "ul" >
< li id = "a" >油条</ li >
< li id = "b" class = "steam" >包子</ li >
< li id = "c" class = "steam" >米饺</ li >
< li id = "d" >< a >鱼粉</ a ></ li >
</ ul >
< script >
// 返回一个元素节点
var el = document.querySelector('li.steam');
el.className='mycolor';
</ script >
</ body >
</ html >
|
示例2 查询多个
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
.steam{
text-decoration: initial;
}
</ style >
</ head >
< body >
< ul id = "ul" >
< li id = "a" >油条</ li >
< li id = "b" class = "steam" >包子</ li >
< li id = "c" class = "steam" >米饺</ li >
< li id = "d" >< a >鱼粉</ a ></ li >
</ ul >
< script >
// 返回多个元素节点
var els = document.querySelectorAll('li.steam');
els[0].className='mycolor';
</ script >
</ body >
</ html >
|
按元素标签查询多个 getElementsByTagName
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
.steam{
text-decoration: initial;
}
</ style >
</ head >
< body >
< ul id = "ul" >
< li id = "a" >油条</ li >
< li id = "b" class = "steam" >包子</ li >
< li id = "c" class = "steam" >米饺</ li >
< li id = "d" >< a >鱼粉</ a ></ li >
</ ul >
< script >
// 按元素标签查询
var els = document.getElementsByTagName('li');
els[2].className='mycolor';
</ script >
</ body >
</ html >
|
查询父节点parentNode
示例
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
.steam{
text-decoration: initial;
}
</ style >
</ head >
< body >
< ul id = "ul" >
< li id = "a" >油条</ li >
< li id = "b" class = "steam" >包子</ li >
< li id = "c" class = "steam" >米饺</ li >
< li id = "d" >< a id = "yufen" >鱼粉</ a ></ li >
</ ul >
< script >
// 查找父节点
var el = document.getElementById('yufen');
el.parentNode.className="mycolor";
</ script >
</ body >
</ html >
|
查找兄弟元素 previousSibling nextSibling
示例
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
.steam{
color: red;
}
</ style >
</ head >
< body >
< ul id = "ul" >
< li id = "ali" >油条</ li >< li id = "bli" >包子</ li >< li id = "cli" >米饺</ li >< li id = "dli" >< a id = "yufen" >鱼粉</ a ></ li >
</ ul >
< script >
// 查找父节点
var tempel = document.getElementById("bli");
tempel.className="steam";
var previousNode = tempel.previousSibling;
previousNode.className="mycolor";
var nextNode = tempel.nextSibling;
nextNode.className="mycolor";
</ script >
</ body >
</ html >
|
兄弟元素查找比较坑,只是能元素在同一行时才能查询。
查询子节点 firstChild lastChild
示例
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
<!DOCTYPE html>
< html >
< head >
< title >访问元素</ title >
< meta charset = "UTF-8" >
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" >
< style >
.mycolor{
color:#fff;
}
.steam{
color: red;
}
</ style >
</ head >
< body >
< ul id = "ul"
>< li id = "ali" >油条</ li
>< li id = "bli" >包子</ li
>< li id = "cli" >< a id = "yufen" >米饺</ a ></ li
>< li id = "dli" >鱼粉</ li
></ ul >
< script >
// 查找子节点
var tempel = document.getElementById("ul");
var firstNode = tempel.firstChild;
firstNode.className = "mycolor";
var lastNode = tempel.lastChild;
lastNode.className = "mycolor";
</ script >
</ body >
</ html >
|
注意,<ul></ul>这段代码,要写成这样才正常查询到。