A pop up window is a little bit like a frame in that there are two pages joined together by the code:  the original page, and the pop up.  Unlike frames, however, there is no Master page.  The code is simply put on the page that leads to the pop up.  

What you need to make up are two pages.  The first is your regular page, and you put a link on that page to open up the pop up window.  The second page you make up contains the information you want to have in your pop up.  

Here's an example.   Open the Popup Window

HERE'S HOW YOU DO IT:

1) Put this code at the top of the page that the window is opening from.  You put the code at the top of your page, between the two tags that say <HEAD> and </HEAD>



 <HEAD>

<SCRIPT LANGUAGE="JavaScript">

<!-- Begin
function popUp(URL) {
day = new Date();
id = day.getTime();
eval("page" + id + " = window.open(URL, '" + id + "', 'toolbars=0, scrollbars=1, location=0, statusbars=0, menubars=0, resizable=0, width=400, height=200');");
}
// End -->
</script>

 2) In my example, the pop up window is a page called "http://www.roxydoll12.com/help/popupwindow.html." Make sure you put in the name that you are going to give to the pop up page on your site.

3)  Now make your pop up page.  Put on it the content you want to show when it pops up.  Remember that it will probably be much smaller, so take this into consideration.

4) Put the following in your html code on the main page where you want  the visitor to click to make the popup window appear.


<A HREF="javascript:popUp('http://www.roxydoll12.com/help/popupwindow.html')">Click Here</A>

Note that in place of "click here" you can write in any message you want to be used to open the window.

5)  You can change the width and height of the dimensions to make your window bigger or smaller.  You can also change the other preferences listed.

For another version of a pop up code and for a pop up window generator check out this Pop Up Window Tool.