JavaScript Document getElementsByName() Method

// Assume: <input type="hidden" name="up">
const upNames = document.getElementsByName("up");

console.log(upNames.length);      // 1
console.log(upNames[0].tagName);  // "INPUT"

const colors = document.getElementsByName("color");
console.log(colors.length); // 3

let selected = "(none)";
for (const radio of colors) {
  if (radio.checked) selected = radio.value;
}
console.log(selected); // e.g. "blue"

const list = document.getElementsByName("item");
console.log("before:", list.length);

const extra = document.createElement("input");
extra.name = "item";
document.body.appendChild(extra);

console.log("after:", list.length); // live list grew (MDN)