如何检查parent是否存在？

let childElement = document.getElementById('childId');
if (childElement.parentNode) {
    console.log('Parent exists.');
} else {
    console.log('Parent does not exist.');
}

let childElement = document.getElementById('childId');
if (childElement.parentElement) {
    console.log('Parent element exists.');
} else {
    console.log('Parent element does not exist.');
}

let childElement = document.getElementById('childId');
if (childElement.parentNode && childElement.parentNode.tagName === 'DIV') {
    console.log('Parent div exists.');
} else {
    console.log('Parent div does not exist.');
}

document.addEventListener('DOMContentLoaded', function() {
    let childElement = document.getElementById('childId');
    if (childElement.parentNode) {
        console.log('Parent exists.');
    } else {
        console.log('Parent does not exist.');
    }
});