DOM div in div
A contains B
let a = document.createElement('div');
a.innerHTML = 'UK';
let b = document.createElement('div');
b.innerHTML = 'England';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
let a = document.createElement('div');
a.innerHTML = 'UK';
let b = document.createElement('div');
b.innerHTML = 'England';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
A contains B, B contains C
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
let a = document.createElement('div');
a.innerHTML = 'UK';
let b = document.createElement('div');
b.innerHTML = 'England';
let c = document.createElement('div');
c.innerHTML = 'London';
document.body.append(a);
a.append(b);
b.append(c);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
A contains B and C
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
let a = document.createElement('div');
a.innerHTML = 'UK';
let b = document.createElement('div');
b.innerHTML = 'England';
let c = document.createElement('div');
c.innerHTML = 'Scotland';
document.body.append(a);
a.append(b);
a.append(c);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
A and B, A contains C
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
let c = document.createElement('div');
c.innerHTML = 'C';
document.body.append(a);
document.body.append(b);
a.append(c);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
A contains B
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
A contains B
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;
let a = document.createElement('div');
a.innerHTML = 'A';
let b = document.createElement('div');
b.innerHTML = 'B';
document.body.append(a);
a.append(b);
let css = document.createElement('style');
document.head.append(css);
css.innerText = `
div{
  border:solid;
  padding: 1ex;
  margin: 1ex;
}
`;