JS tool

function keepElement(selector, fatherSelector, elementToAdd) {
    setInterval(() => {
        const element = document.querySelector(selector);
        if (!element) {
            const father = document.querySelector(fatherSelector);
            if (!father) return;
            father.insertBefore(elementToAdd, father.firstChild);
        }
    }, 100)
}
function htmlToNode(html) {
    const template = document.createElement('template');
    template.innerHTML = html;
    const nNodes = template.content.childNodes.length;
    if (nNodes !== 1) {
        throw new Error(
            `html parameter must represent a single node; got ${nNodes}. ` +
            'Note that leading or trailing spaces around an element in your ' +
            'HTML, like " <img/> ", get parsed as text nodes neighbouring ' +
            'the element; call .trim() on your input to avoid this.'
        );
    }
    return template.content.firstChild;
}