JavaScript Получите ребенка по имени
let myForm = document.getElementById('form');
let child = myForm.querySelector('input[name="username"]');
console.log(child);
garzj
let myForm = document.getElementById('form');
let child = myForm.querySelector('input[name="username"]');
console.log(child);var child_element = document.querySelector("#id").children[0];
//Where # defines id and '.' a class. And 0 argument the first child element