What is the essence of writing a code in javascript to change the elements of HTML body tags...

Question

The usefulness of
var x = document.getElementsByClassName(" ");
X.appendChildNode(" ");

Answer 1

thus, you can hide unnecessary elements and create, show new ones without reloading the page itself. it is important. once loaded, the web page no longer accesses the server with background data. all interaction takes place on the client side. this way you can create interactivity or games