Form Clone

Element.addMethods('FORM', {
    clone: function(form, id){
    
        // if no id was passed use native clone
        if( ! Object.isString(id) ) return Element.clone(form, id);

        var form = Element.clone(form, true);
        form.writeAttribute('id', id);

        // change elements with id attr
        var origId, idElements = form.select('[id]');
        idElements.each(function(elem){
            origId = elem.identify();
            elem.writeAttribute('id', id+'_'+origId);
        });

        return form;
    }
});