An ordinary <a> link, like this one, causes the browser to open the new page in the same browser window:
<a href="http://www.boutell.com/">Visit Boutell.Com, Inc.</a>
If we give the link a target attribute, we can follow the link in a new window:
<a href="http://www.boutell.com/" target="outside">Visit Boutell.Com, Inc.</a>
This link will open a new window the first time it is used and give that window the name outside. This isn't something the user sees— it's just a special window "nickname" for you, the web designer.
If we click on a second link that also has a target of outside, and the outside window is still open, it will be used again.
Most of the time, this is a good thing— users don't like dozens of windows piling up as they navigate your site. But if you do want to force a completely new window for every click, you can use the special target value _blank (don't forget the _). _blank always opens a new, unnamed window.
For more advanced uses of the target attribute, see how can a link in one window send another window to a new page?
It's also possible to open new windows of a specific size, to center those windows, and to resize a window so that the useful space inside matches your layout. See the articles how do I open a new window of a certain size, how do I center a browser window on the screen, and How do I make the window size match my layout?
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