อยากให้ POP UP ยึดติดกับหน้าจอ ไม่ว่าจะเปิดไปแท็บใดๆ ต้องทำอย่างไรครับ

.banner { 
position:fixed; 
bottom:0;
right:0; 
margin:auto; 
width:200px; 
height:100px; 
z-index:500;
}

<div class="banner">
<img src="รูปภาพ" /></div>
</body>

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Because of the disadvantages of these two built-in modal windows, web designers try to use the browser popup window as a modal window, but there are problems with this approach, too.

Ordinary popup windows will disappear behind other windows when you click outside their borders. Open an ordinary popup window and try it. These little popup windows fall behind other windows, they get lost and might never get closed. In contrast, a modal window always stays on top, in your face, until the programmer or the user closes it.
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...
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Because of the disadvantages of these two built-in modal windows, web designers try to use 
the browser popup window as a modal window, 
but there are problems with this approach, too.

http://web.archive.org/web/20101125011545/http://getyourwebsitehere.com/jswb/modwin/modalwinparent.html#code

Ordinary popup windows will disappear behind other windows when you click outside their borders. 
Open an ordinary popup window and try it. 
These little popup windows fall behind other windows, they get lost and might never get closed. 
In contrast, a modal window always stays on top, in your face, until the programmer or the user closes it.