how to remove all children untill reach node code example

Example 1: delete all childs in node

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

Example 2: js remove child elements

function deleteChild() { 
        let e = document.querySelector("ul"); 
        
        //e.firstElementChild can be used. 
        let child = e.lastElementChild;  
        while (child) { 
            e.removeChild(child); 
            child = e.lastElementChild; 
        } 
    } 
    let btn = document.getElementById( 
    "btn").onclick = function() { 
        deleteChild(); 
    }