勝手にclass制御の動的なやつに追従してなんかやりたい時

勝手にclass制御の動的なやつに追従してなんかやりたい時に暴挙
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<ul id=”ul”><li><p>testtest</p></li></ul>
<script>
window.onload = function(){
fetchDom();
}
function fetchDom() {
let parent = document.getElementById(“ul”); //ul親
let children = parent.getElementsByTagName(“li”); //li子
children = Array.from(children); //HTMLCollection→forEach
const mo = new MutationObserver(records => {
children.forEach(function (elm) {
if (elm.classList.contains(“target”)) {
let word = elm.getElementsByTagName(“p”)[0];
word.innerText = “test”;
}
});
});
mo.observe(parent, {
attributes: true, //属性監視
subtree: true //子孫監視
});
}
</script>