FragBuilder

FragBuilder.js

var FragBuilder = (function() {
    var applyStyles = function(element, style_object) {
        for (var prop in style_object) {
            element.style[prop] = style_object[prop];
        }
    };
    var generateFragment = function(json) {
        var tree = document.createDocumentFragment();
        json.forEach(function(obj) {
            for (part in obj) {
                var el = document.createElement(part);
                if ('children' in obj[part]) {
                    el.appendChild(generateFragment(obj[part].children));
                    delete obj[part].children;
                }
                if ('style' in obj[part]) {
                    applyStyles(el, obj[part].style);
                    delete obj[part].style;
                }
                if ('text' in obj[part]) {
                    el.appendChild(document.createTextNode(obj[part].text));
                    delete obj[part].text;
                }
                for (var attr in obj[part]) {
                    el.setAttribute(attr, obj[part][attr]);
                }
                tree.appendChild(el);
            }
        });
        return tree;
    };
    return {
        'build': generateFragment
    };
}());

http://jsfiddle.net/rlemon/GPRte/2/ simple demo

new update accepts frags as json. http://jsfiddle.net/rlemon/GPRte/4/