count the number of existing tabs in jquery?

I'm using a dynamic jQuery tab widget to add/remove tabs generated programmatically.

How do I check through jQuery and count how many existing tabs are present in the widget?

I'm using this code, but it doesn't work:

$('#container-1 > ul').tabs('add', tabName, name);

var newTab;

if ($('#container-1 > li').size() < 0) {
    newTab = $(tabName).css('display', 'block')
} else {
    newTab = $(tabName).css('display', 'none');
}

newTab.html('<iframe src="ViewPatient.aspx?pname=' + name 
       + '" width="100%" frameborder="0" scrolling="no" height="300"></iframe>');