Can not add second tab with iframe

Can not add second tab with iframe

I need add tabs to my page dynamically (use iframe as container)
var $tabs = $("#main").tabs({
    cache: true,
    add: function(event, ui) {
    $tabs.tabs('select', '#' + ui.panel.id);
    }
    , select: function(event, ui) {
    var url = $.data(ui.tab, 'load.tabs');
    if (url) {
        $('#' + ui.panel.id).attr("src", url);
    }
    return true;
    }      
    , panelTemplate: '<iframe id="a-tab-panel" src=""></iframe>'
});
$("#li1").click(function() {
    $tabs.tabs('add', 'a.aspx', 'tab1');
//page with jquery.js included
});
$("#li2").click(function() {
    $tabs.tabs('add', 'b.aspx', 'tab2')
//page without jquery.js
});

if you use #li2 to add tab, it work's fine, if you use #li1, only one tab can be add, the others can not load content.
I have debug the code ,it seem's $.data(ui.tab, 'load.tabs') can not get a valid value.