Get all unique tags in a page

get_all_unique_tags.js

/* Get List of Unique Tags used in the page
 * @author: Livingston Samuel
 */

var uniqueTags = (function (win, doc) {
    var allElems = doc.getElementsByTagName('*'),
        len = allElems.length, elem, tags = {}, arr = [];

    while(len--) {
        elemName = allElems[len].nodeName;
        if(!tags.hasOwnProperty(elemName)) {
            tags[elemName] = true;
            arr.push(elemName);
        }
    }

    delete tags;
    delete allElems;

    return (arr.sort().join(', ').toLowerCase());
}(window, document));