Inserting HTML elements with JavaScript

Instead of directly messing with innerHTML it might be better to create a fragment and then insert that:

function create(htmlStr) {
    var frag = document.createDocumentFragment(),
        temp = document.createElement('div');
    temp.innerHTML = htmlStr;
    while (temp.firstChild) {
        frag.appendChild(temp.firstChild);
    }
    return frag;
}

var fragment = create('<div>Hello!</div><p>...</p>');
// You can use native DOM methods to insert the fragment:
document.body.insertBefore(fragment, document.body.childNodes[0]);

Benefits:

1. You can use native DOM methods for insertion such as insertBefore, appendChild etc.
2. You have access to the actual DOM nodes before they're inserted; you can access the fragment's childNodes object.
3. Using document fragments is very quick; faster than creating elements outside of the DOM and in certain situations faster than innerHTML.

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Even though innerHTML is used within the function, it's all happening outside of the DOM so it's much faster than you'd think...

You want this

document.body.insertAdjacentHTML( 'afterbegin', '<div id="myID">...</div>' );