How to split n element by using js

I need to show specific content for users who can edit and view.

I am trying to get specific html element for rich editor . - user can edit inside this div content content - user can only read classname="header"

<div classname="main">

<div classname="header"> it can be read only</div>

<div classname="contenteditable">it can be edit only</div> </div> How can i do this by using reactjs