1var myDiv = document.getElementById("myDivID");
2    myDiv.innerHTML = "";//remove all child elements inside of myDiv

1// Get the <ul> element with id="myList"
2let list = document.getElementById("myList");
3
4// As long as <ul> has a child node, remove it
5while (list.hasChildNodes()) {  
6  list.removeChild(list.firstChild);
7}

1function deleteChild() { 
2        let e = document.querySelector("ul"); 
3        
4        //e.firstElementChild can be used. 
5        let child = e.lastElementChild;  
6        while (child) { 
7            e.removeChild(child); 
8            child = e.lastElementChild; 
9        } 
10    } 
11    let btn = document.getElementById( 
12    "btn").onclick = function() { 
13        deleteChild(); 
14    } 

1document.getElementById("myDivID").innerHTML = "";

1document.getElementById("myId").innerHTML = '';