target=_blank not work

[kevinsir]

hey guys;
I have a problom.
when I set something just like 'before all' before html head '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"' target=_blank in head not work,but when i delete 'before all' it works;
That's the code.

before all
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>

<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
    <title>dsasad</title>
     <base target=_blank />
</head>
<body>
<p>
<a href="http://opensuse.javaeye.com"> the link</a>
 </p>

</body>
</html>

the link not open in new window
if i drop 'before all '

the link open in new windos

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head>

<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
    <title>dsasad</title>
     <base target=_blank />
</head>
<body>
<p>
<a href="http://opensuse.javaeye.com"> the link</a>
 </p>

</body>
</html>

Well, who can tell me the reason?
More, I test it in IE8.0

[drhowarddrfine]

Nothing is to be before the doctype. It throws IE into quirks mode. That shouldn't affect the link, however.