Answers for "firstchild html"

first child element javascript

Both these will give you the first child node:

console.log(parentElement.firstChild); // or
console.log(parentElement.childNodes[0]);

If you need the first child that is an element node then use:

console.log(parentElement.children[0]);

first-child

p:first-child {
  background-color: yellow;
}