Cross platform way of insertHTML().

insert_html.js

/**
 * @param {HTMLElement} el
 * @param {String} where beforeBegin、afterBegin、beforeEnd、afterEnd
 * @param {String} html
 */
function insertHTML(el, where, html) {
    if (!el) return false;

    where = where.toLowerCase();

    if (el.insertAdjacentHTML) {//IE
        el.insertAdjacentHTML(where, html);
    } else {
        var range = el.ownerDocument.createRange(),
            frag = null;

        switch (where) {
            case 'beforebegin':
                range.setStartBefore(el);
                frag = range.createContextualFragment(html);
                el.parentNode.insertBefore(frag, el);
                return el.previousSibling;
            case 'afterbegin':
                if (el.firstChild) {
                    range.setStartBefore(el.firstChild);
                    frag = range.createContextualFragment(html);
                    el.insertBefore(frag, el.firstChild);
                } else {
                    el.innerHTML = html;
                }
                return el.firstChild;
            case 'beforeend':
                if (el.lastChild) {
                    range.setStartAfter(el.lastChild);
                    frag = range.createContextualFragment(html);
                    el.appendChild(frag);
                } else {
                    el.innerHTML = html;
                }
                return el.lastChild;
            case 'afterend':
                range.setStartAfter(el);
                frag = range.createContextualFragment(html);
                el.parentNode.insertBefore(frag, el.nextSibling);
                return el.nextSibling;
        }
    }
};