Dears, thanks i modify the c.html as follow:

<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Transitional//EN'

<html xmlns=‘’ xml:lang=‘en’ lang=‘en’>
    <title>For demo purpose only :: &1</title>
    <link rel=‘STYLESHEET’ type=‘text/css’ href=‘codebase/dhtmlxtabbar.css’>
    <script src=‘codebase/dhtmlxcommon.js’></script>
    <script src=‘codebase/dhtmlxtabbar.js’></script>


         <div id=‘a_tabbar11’ class=‘dhtmlxTabBar’  style=‘width:1024; height:420px;’>    
                    tabbar=new dhtmlXTabBar(‘a_tabbar11’,‘left’,50);
when load d.xml,no any error be caused, but if i delete the code: ‘<h1>C</h1>’, then i have meet the javascript error.

You have missed body tag, as result HTML not parsed correctly and may cause different errors.