如何在不使用元素索引的情况下搜索某个父元素下的特定元素

var parentElement = document.getElementById("parent");
var childElements = parentElement.querySelectorAll("div");

var parentElement = document.getElementById("parent");
var childElements = [];

for (var i = 0; i < parentElement.childNodes.length; i++) {
  var node = parentElement.childNodes[i];
  if (node.nodeName === "DIV") {
    childElements.push(node);
  }
}

var parentElement = $("#parent");
var childElements = parentElement.find("div");