remove everything in body javscript code example

Example 1: delete all childs in node

while (myNode.firstChild) {
  myNode.removeChild(myNode.lastChild);
}

Example 2: Remove all child nodes of a list:

// Get the <ul> element with id="myList"
let list = document.getElementById("myList");

// As long as <ul> has a child node, remove it
while (list.hasChildNodes()) {  
  list.removeChild(list.firstChild);
}