JS function: replace tag name but keep element contents. Source: http://stackoverflow.com/a/15086834/552067

change-tag.js

// Replace tag name but keep element contents
function changeTag(el, newTagName, keepAttributes) {
	var newEl = document.createElement(newTagName);

	// Copy the children
	while (el.firstChild) {
		newEl.appendChild(el.firstChild); // *Moves* the child
	}

	// Copy the attributes
	if (keepAttributes) {
		for (var i = el.attributes.length - 1; i >= 0; --i) {
			newEl.attributes.setNamedItem(el.attributes[i].cloneNode());
		}
	}

	// Replace it
	el.parentNode.replaceChild(newEl, el);
}