Unwrap a DOM element
Remove the parents of an element from the DOM, leaving the element's content in place.
How to unwrap an element with cross browser safe DOM methods:
// select element to unwrap
var el = document.querySelector('div');
// get the element's parent node
var parent = el.parentNode;
// move all children out of the element
while (el.firstChild) parent.insertBefore(el.firstChild, el);
// remove the empty element
parent.removeChild(el);
The code is straight forward and much faster than the corresponding jQuery's method $.unwrap().