How to create dynamic HTML?

Question

with out a library, given an anchor element.

so render(anchor_element) will render content in the browser.

I'm asking about the best approach. My idea was to use HTMLToElement and from there apply CSS to it which has already been loaded.

$P.HTMLToElement = function (html) {
    var div = document.createElement('div');
    div.innerHTML = html;
    return div.firstChild;
};