return a querySelector for given DOMElement

getSelector.js

/**
	 * return a selector to use with document.querySelector to retrieve given node
	 * @param {DOMElement} node
	 * @returns {string}
	 */
	function getSelector(node){
		// check for node.id avoiding autogenerated ids by ignoring any ids containing numeric values
		// and checking that the id is unique in the document.
		if (node.id && node.id.match(/^\D+$/) && document.querySelectorAll(node.id).length === 1) {
			return '#' + node.id;
		}

		// if node is body don't make any other lookup
		if (node === document.body) {
			return 'body';
		}

		// making a "more complex" node selector
		var parent = node.parentNode, tagName = node.tagName;

		// if only one child of type inside the parent made a simple tag selector
		if (parent.querySelector(tagName).length === 1) {
			return getSelector(parent) + '>' + tagName;
		}

		var prevSibling = node, nthOfType = 1;
		// finally end up selecting the node by its nthOfType
		while(prevSibling = prevSibling.previousElementSibling) {
			prevSibling.tagName === tagName && ++nthOfType;
		}
		return getSelector(parent) + '>' + tagName + ':nth-of-type(' + nthOfType + ')';
	}