Can be done with MutationObserver:

function handleSomeDiv(someDiv) { 

    console.log("div was handled");

}



const observer = new MutationObserver(function (mutations, mutationInstance) {

    const someDiv = document.getElementById('some-div');

    if (someDiv) {

        handleSomeDiv(someDiv);

        mutationInstance.disconnect();

    }

});





observer.observe(document, {

    childList: true,

    subtree:   true

});