React input Revocation

2. Functions that can be used in the destroy phase:
   Componentwillunmount: Cleanup operations, such as timers and event listeners, before the components are removed. Because these functions are manually added by the developer, react does not know that it must be cleaned manually.
   
   
3. Instance
   The first way: in Render, the previous page is removed, reflected in the page, is to delete it.
   

   <! DOCTYPE html>
   Input other does not trigger
   
   
   
   When I enter 123,
   
   
   
   The second type is to use a function provided by react Unmountcomponentatnode
   
   <! DOCTYPE html>
   if (Event.target.value = = "123") {React.unmountcomponentatnode (document.getElementsByTagName ("body") [0]);                Return            } this.setstate ({name:event.target.value});                    }, Render:function () {return <div> 
   

React input Revocation