JS How to get a child label for an ID

Idea: Get the parent object by ID, and then use ChildNodes to get all the child object arrays, the key code:

document.getElementById (div_id). ChildNodes; Array of sub-objects

Example Demo: Click the button to add a red class for all the child tags of the div tag with ID test, that is, the font is displayed

1. HTML structure

<div id = "TEST" >
<a href= "#" > I am a hyperlink </a>
<input type= "text" value= "I am text box" >
<div> I am a son div</div>
</div>
<input type= ' button ' value= ' Set child element style ' onclick= ' fun () '/>

2. CSS style

. red{color:red!important;}

3. JavaScript code

function Fun () {
OBJS = document.getElementById ("Test"). ChildNodes;
For (k in Objs)
Objs[k].classname = "Red";
}

4, before and after the comparison effect is as follows

JS How to get a child label for an ID