How to get whole element, innerHTML gets only inner part?

I have a function that gets the product and the id of this product, I need to put the entire HTML into local storage, I try it like this, but the innerHTML gets only the inner part, please tell me how to fix it?

function storagePlusQuantity(product, productId) {
    const storageId = 'product' + productId;
    localStorage.removeItem(storageId);
    localStorage.setItem(storageId, product);

    console.log(product)

}

The photo shows an example of the product of which I receive a functionenter image description here

>Solution :

If you have code like this:

<div id="outer-div">
~~something~~
</div>

getting the innerHTML of the div will only get the ~~something~~ part.

What you want to do is just get the div with outerHTML.

See codepen example: See Codepen Here