How to set DOM element as first child?

I have an element E and I’m appending some elements to it. All of a sudden, I find out that the next element to append should be the first child of E. What’s the trick, how to do it? Method unshift doesn’t work because E is an object, not array.

Long way would be to iterate through E’s children and to move’em key++, but I’m sure that there is a prettier way.

Answer

var eElement; // some E DOM instance
var newFirstElement; //element which should be first in E

eElement.insertBefore(newFirstElement, eElement.firstChild);