How to create a DOM node as an object?

I'd put it in the DOM first. I'm not sure why my first example failed. That's really weird.

var e = $("<ul><li><div class='bar'>bla</div></li></ul>");
$('li', e).attr('id','a1234');  // set the attribute 
$('body').append(e); // put it into the DOM     

Putting e (the returns elements) gives jQuery context under which to apply the CSS selector. This keeps it from applying the ID to other elements in the DOM tree.

The issue appears to be that you aren't using the UL. If you put a naked li in the DOM tree, you're going to have issues. I thought it could handle/workaround this, but it can't.

You may not be putting naked LI's in your DOM tree for your "real" implementation, but the UL's are necessary for this to work. Sigh.

Example: http://jsbin.com/iceqo

By the way, you may also be interested in microtemplating.

Try this:

var div = $('<div></div>').addClass('bar').text('bla');
var li = $('<li></li>').attr('id', '1234');
li.append(div);

$('body').append(li);

Obviously, it doesn't make sense to append a li to the body directly. Basically, the trick is to construct the DOM elementr tree with $('your html here'). I suggest to use CSS modifiers (.text(), .addClass() etc) as opposed to making jquery parse raw HTML, it will make it much easier to change things later.

var template = $( "<li>", { id: "1234", html:
  $( "<div>", { class: "bar", text: "bla" } )
});
$('body').append(template);

What about this?

First make your template into a jQuery object:

 var template = $("<li><div class='bar'>bla</div></li>");

Then set the attributes and append it to the DOM.

 template.find('li').attr('id','1234');
 $(document.body).append(template);

Note that it however makes no sense at all to add a li directly to the DOM since li should always be children of ul or ol. Also it is better to not make jQuery parse raw HTML. Instead create a li, set its attributes. Create a div and set it's attributes. Insert the div into the li and then append the li to the DOM.