How to make a popup window?

This is the simplest implementation, although it cannot specify the window title:

<script language="JavaScript" >
alert('Congratulations!');
</script >

2007-05-12 18:06:09 補充：
You may write a function, call it as needed:<script language="JavaScript">function congrat(){　alert('Congratulations!');}</script>Call it:<script language="JavaScript">……if (……)　congrat();else　…………</script>

2007-05-12 20:52:44 補充：
Please ignore the above scrambled code.<script language="JavaScript">function congrat(){　alert('Congratulations!');}</script>Call it by:<script language="JavaScript">……if (……)　congrat();else　…………</script>

2007-05-12 20:55:43 補充：
Please ignore the above scrambled code.<script language="JavaScript" >function congrat(){　alert('Congratulations!');}</script >Call it by:<script language="JavaScript" >……if (……)　congrat();else　…………</script >