unwrap.js

// remove parent without removing childen
function unwrap(wrapper) {
	// place childNodes in document fragment
	var docFrag = document.createDocumentFragment();
	while (wrapper.firstChild) {
		var child = wrapper.removeChild(wrapper.firstChild);
		docFrag.appendChild(child);
	}

	// replace wrapper with document fragment
	wrapper.parentNode.replaceChild(docFrag, wrapper);
}