原生js获取body/id/class/img/li

获取body/id/class/img/li

1.获取body

doucumnet.body
document.getElementsByTagName("body")[0]

2.获取id

document.getElementById("id")

3.获取class

document.getElementsByClassName("class")

4.获取img/li

document.getElementsByTagName("img")
document.getElementsByTagName("li")

HTML DOM Document 对象

附上菜鸟教程地址：
https://www.runoob.com/jsref/dom-obj-document.html