constructor for building xml like strings

gistfile1.js

// extracted from an earlier gist that had a more comprehensive DOM-like implementation
// in this case, I didn't care about namespaces and I didn't require any operation but
// append. This is too basic to be useful for most things, but good enough for what I've
// used it for. Note that the use of ES5 accessors makes this incompatible with IE < 9.

function Tag (name) {
    this.name = name;
    this.attrs = Object.create(null);
    this.children = [];
    return this;
}

Tag.prototype = {
    get first () {
        return this.children[0];
    },
    get last () {
        return this.children[this.children.length - 1];
    },
    getAttrs: function () {
        var a = this.attrs, p, r = [];
        for (p in a) r.push(' ', p, '="', a[p], '"');
        return r.join('');
    },
    append: function (node) {
        if (node instanceof Tag) {
            if (this.children.length > 1) {
                node.prev = this.last;
                this.last.next = node;
            }
            node.parent = this;
        }
        this.children.push(node);
    },
    toString: function () {
        var open  = this.name == 'text' ? [''] : ['<', this.name, this.getAttrs(), '>'],
            close = this.name != 'text' ? this.children.length ? ['</', this.name, '>'] : [' /' + open.pop()] : [''];

        this.children.forEach(function (child) {
            open.push(child.toString());
        });

        return (open.join('') + close.join(''));
    }
};

Tag.prototype.constructor = Tag;