HTML Divs Can Go Outside Browser Window?

I was playing around with ASP.NET Web Parts which has a 'drop down' div. It's all the way to the right of the page. When I click to bring it up, it goes off the window. Usually

Solution 1:

It is indeed the createPopup method that does the trick. It's a proprietary method in Internet Explorer.

See http://msdn.microsoft.com/en-us/library/ms536392%28VS.85%29.aspx.

Solution 2:

Why not add a little extra to the margin there? Seems like the most easiest and cheapest way to save time.